JPH07100401B2 - Twin wheel caster - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to furniture, office equipment, transportation equipment, mobile equipment,
In addition, the present invention relates to improvement of a twin-wheel caster that is mounted and used.

[Prior art]

As is well known, casters that are widely used have a direction changing function in addition to a running function. As for such casters, it is practically preferable that the casters are provided with a lock means for restraining wheels for traveling the casters and a lock means for restraining a turning shaft for turning the casters (for changing direction). As such a locking means, the locking claw of the braking plate is locked in the locking groove of the inner circumference of the wheel to restrain the rotation of the wheel (prior art 1), which is disclosed in JP-A-61-33302. As shown in the figure, lock the swing shaft locking tool and the wheel locking claw of the lock slider to the lock receiving part that is integrally provided at the lower end of the swing shaft and the locking groove on the inner circumference of the wheel. Thus, there is known a device (prior art 2) that locks a wheel and a turning shaft at the same time.

[Problems to be Solved by the Invention]

The locking means of the prior art 1 only stops the rotation of the wheels, and cannot stop the turning motion of the caster mainly about the turning axis. When a device having such casters is stopped at a predetermined position or placed in a limited place, it takes time to secure a fixed position because the device swings due to the turning motion of the casters. Especially on an inclined surface, the caster may change direction due to the weight of the device, which may cause an unexpected accident. The locking means of the prior art 2 is excellent in that the wheels and the turning shaft can be locked. However, since the wheels and the turning shaft are locked and unlocked at the same time, the wheels are in the unlocked state and the turning shaft. It is not easy to use because the casters cannot be locked in the locked state and the traveling direction of the casters cannot be determined. In addition, the lock slider for pivotal lock operation is located at the bottom of the caster and is exposed to the outside, so that while the caster is running, another object collides with the lock slider and the wheels and pivot shaft are inadvertently locked. Sometimes.

[Object of the Invention]

In view of such a technical problem, the present invention is to submit a stable twin-wheel caster in which individual locking of wheels and a turning shaft and simultaneous locking can be performed, and moreover, the wheels and the turning shaft are not locked in an unexpected situation. It is what

[Means for Solving the Problems]

The twin-wheel caster according to the present invention is characterized by the following means for solving the problems in order to achieve the intended purpose. That is, with reference to the accompanying drawings, it has an outer wall 6a whose lower side is open, an inner wall 6b protruding from an axially intermediate portion of the inner surface of the outer wall, and a shaft hole 8 extending from the upper side to the lower side of the outer wall 6a. A pair of caster traveling wheels 1 in which a support 6 and a locking groove 2 parallel to the rotation axis are circumferentially adjacent to each other and are distributed over the entire inner peripheral surface,
1 ', an axle 5 for these wheels, and a swivel axle 10 for turning the casters, and an axle 5 horizontally penetrating the inner wall 6b of the support 6 is rotatably supported by the inner wall 6b. In addition, a pair of wheels 1, 1'arranged on both sides of the inner wall 6b are attached to both ends of the axle 5,
In the twin-wheel caster in which the swivel shaft 10 is rotatably mounted in the shaft hole 8 of the support body 6, a lock pin 20 for locking the pair of wheels 1, 1 ′ and a lock pin 20 are provided as components other than the above. A spring 21 for giving an elastic force to the, a pair of operation plates 22 for operating the lock pin 20, and an operation lever 24 for these operation plates.
And a pair of lock members 16 for locking the pivot shaft 10.
And a pair of slide members 17 for operating these lock members,
18 is included, and both lock members 16 are coil winding spring-shaped one-way clutches 16a and 16b whose coil winding directions are different from each other, and both slide members 17 and 18 for operating these lock members are Of the two operation plates 22 having a cam surface 17a, 18a at one end thereof, and each of the operation plates 22 is a guide elongated hole for moving a lock pin formed on a locus circle centered on a fulcrum 25 of these plate surfaces. 27, and three sets of locking recesses 28, 29, 30 formed on the outer peripheral edge of the guide elongated hole 27 for engaging and holding the lock pin 20 and having relatively different circumferential positions and radial depths. And a cam portion 31 for pushing the lock member formed on the free end side of both operation plates 22, respectively.
The cam surfaces 31a and 31b corresponding to the cam surfaces 17a and 18a of the
That is formed on the cam portion 31 of 22 and that an opening window 26 for connecting both operation plates 22 and the operation lever 24
Is formed on the outer wall 6a of the support body 6, and a holding hole 19 for mounting the lock pin 20 and the spring 21 is formed on the inner wall 6b of the support body 6, and supports both operation plates 22 and the support plate 22. A guide hole 6c for communicating with the shaft hole 8 of the body 6 is formed at a boundary portion between the support inner wall 6b and the shaft hole 8, and the inner wall 6b of the support 6 and both wheels 1, 1 Both operating plates 22 disposed between the two operating plates 22 and ′ are rotatably supported by penetrating the fulcrums 25 by the axle 5, and the operating plates 22 and the operating lever 24 are connected to each other for operation. The operating end of the lever 24 protrudes outside the support 6 from the opening window 26 of the support outer wall 6a, and penetrates the holding hole 19 of the support inner wall 6b and the guide long holes 27 of both operation plates 22. Both ends of the wheel lock pin 20 intervening on the inner surface side of both wheels 1, 1 ′ are locked grooves 2 of both wheels 1, 1 ′.
And the spring 21 held by the holding hole 19 of the support inner wall 6b.
Pushes the lock pin 20 in a direction to engage with each locking groove 2, and the swivel shaft 10 is rotatably inserted into the shaft hole 8 of the support body 6,
Further, both lock members 16 are interposed between the inner and outer peripheral surfaces of the shaft hole 8 and the turning shaft 10, and both slide members 17 and 18 in which the end portions having the cam surfaces 31a and 31b are opposite to each other are the support members. 6, one end and the other end of both lock members 16 are slidably inserted in the guide hole 6c of 6 and are fixed to the inner surface of the shaft hole 8 and the slide members 17 and 18, respectively. The cam surfaces 31a and 31b of the cam portion 31 of the plate 22 and the cam surfaces 17a and 18a of the slide members 17 and 18 face each other so that they can come into relative contact with each other, and the guide elongated holes in the operation plates 22. Three sets of locking recesses 28, 29, which are formed on the outer peripheral edge of 27 and have different positions and depths,
Of the 30, both operation plates that lock the turning shaft 10 through both lock members 16 that are associated with both cam portions 31 and both slide members 17 and 18
When 22 is rotationally displaced to the position where the swing shaft 10 is unlocked, the lock pin 20 is engaged inside and both of these wheels 1, 2,
A set of locking recesses 28 for disengaging from the locking groove 2 of 1 '
Is inside the circumferential portion connecting the open ends of the respective locking grooves 2 and does not overlap these locking grooves 2, and both operating plates 22
Occupies a position that overlaps with the holding hole 19 of the support inner wall 6b in the rotational displacement posture of, and both operation plates 22 through both lock members 1 linked with both cam portions 31 and both slide members 17, 18. When the wheel is rotationally displaced to a position where the swivel shaft 10 is locked, another set of locks for engaging the lock pin 20 inside and disengaging this from the lock groove 2 of both wheels 1, 1 ' The recess 29 is located inside the circumferential portion connecting the open ends of the locking grooves 2 and does not overlap the locking grooves 2, and in the rotational displacement posture of both operation plates 22, the inner wall 6 b of the support body is in contact. It occupies a position where it overlaps with the holding hole 19, and is rotationally displaced to a position where both operation plates 22 lock the swivel shaft 10 through both lock members 16 that are linked to both cam portions 31 and both slide members 17 and 18. The lock pin 20 is engaged inside, The remaining one set of locking recesses 30 for engaging the locking grooves 2 of 1 and 1'is the two sets of locking recesses 2 described above.
It has a depth greater than 8 and 29 and is located at a position where it overlaps with the locking groove 2 facing the locking recess 30, and in the rotational displacement posture of both operation plates 22, the holding hole of the support inner wall 6b.
It is characterized in that it also overlaps 19 and occupies the position where it engages with each one locking groove 2 of both wheels 1, 1 '.

[Action]

In the case of the twin-wheel caster according to the present invention, both operation plates 22 are rotationally displaced via the operation lever 24, and the lock pin 20 is engaged with any of the three sets of locking recesses (28, 29, 30). In the above, when the lock pin 20 is engaged with the pair of locking recesses 28, the cam portion 31 and the lock member linked to the cam portion 31.
Both operation plates 22 that lock the swivel shaft 10 via 16 are rotationally displaced to a position where the swivel shaft 10 is unlocked, and the lock pin 20 is disengaged from the locking groove 2 of both wheels 1, 1 '. are doing. In this state, both wheels 1, 1'and the turning shaft 10 can freely move in a predetermined direction. In the above, when the lock pin 20 is engaged with the other set of the recessed recesses 29, both operation plates 22 lock the swivel shaft 10 via the cam portion 31 and the lock member 16 linked thereto. It is rotationally displaced to the position where
It is disengaged from the locking groove 2 of 1 '. In this state, both wheels 1, 1'can rotate freely, but the turning shaft 10
Can't move. In the above, when the lock pin 20 is engaged with the remaining set of the locking recesses 30, both operation plates 22 lock the swivel shaft 10 via the cam portion 31 and the lock member 16 linked thereto. It is rotationally displaced to the position and the lock pin 20
It is engaged with the locking groove 2 of 1 '. In this state, neither of the wheels 1, 1'and the turning shaft 10 can move.

【Example】

A first embodiment of a twin-wheel caster according to the present invention will be described.
This will be described with reference to FIGS. In FIGS. 1 to 3, two wheels 1 and 1 ′ having the same outer diameter have an arcuate locking groove 2 on an inner peripheral surface of a ring shape, and a shaft is provided on a central boss portion 4. It has a hole 3. In FIG. 2, the support body 6 seen in the center of the figure extends from the outer wall 6a for covering the upper peripheral surfaces of the wheels 1 and 1'and the widthwise intermediate portion of the inner surface of the outer wall 6a while maintaining the elevated shape. inner wall
6b, and the lower side is open. In the support body 6, the boss portion 7a formed on the inner wall 6b has a shaft hole 7 that horizontally penetrates the inner wall 6b, and at one side of the support body 6, a shaft hole 8 whose bottom is closed is formed. It is provided from the upper side to the lower side of the outer wall 6a. As is apparent with reference to FIG. 2, on the upper end side of the shaft hole 8, an opening projecting edge 9 having two vertically divided slits 9a and a male screw 9b on the outer peripheral surface is formed. Edge 9 is the outer wall
6a, the shaft hole 8 has a third
As is clear with reference to the drawings, two groove portions 8a extending in the vertical direction are formed so as to face each other. As clearly shown in FIG. 2, the swivel shaft 10 has a lower end portion and an upper end portion as small diameter portions 10a, and these small diameter portions 1
The middle part of 0a is formed as a large diameter part 10b. Two collars 11 and 12 corresponding to both small diameter parts 10a of the swivel shaft 10.
The projections 11a, 12a are formed on the outer periphery of these end portions, and the bearing 13 for supporting the lower end of the swivel shaft 10 is made of a steel ball and supports the circumferential surface of the swivel shaft 10. The bearing 14 is a bearing, and the tightening member 15 for holding the swivel shaft 10 in a fixed position is a ring-shaped cap having a female screw corresponding to the male screw 9b of the opening flange 9. The axle 5 for both wheels passes through the shaft hole 7 of the inner wall 6b and is bossed.
It is rotatably supported by 7a, and both wheels 1, 1'are attached to both ends of the axle 5. In the case of the swivel shaft 10, it is rotatably mounted in the shaft hole 8 of the support 6 as exemplified below. That is, the shaft hole 8
The ball bearing 13 is fitted to the bottom of the swivel shaft 10, both collars 11 and 12 are fitted to the outer circumferences of the upper and lower ends of the swivel shaft 10, and the radial bearing 14 is fitted to the outer periphery of the swivel shaft 10 above the collar 11. The swivel shaft 10 and the members attached to the swivel shaft 10 are inserted into the shaft hole 8 so that the protrusions 11a and 12a of the collars 11 and 12 and the groove portions 8a of the shaft hole 8 are relatively engaged with each other. The fastening member 15 is fastened to the opening projection edge 9. Means A for locking the pivot 10 are as illustrated below. Referring to FIG. 2 and FIG. 3, the lock member 16 for locking the turning shaft has coil winding springs whose coil winding directions are opposite to each other, that is, a pair of one-way clutches 16a and 1a.
It consists of 6b. Each one-way clutch 16a, 16b has projecting pieces 16c, 16d, 16e, 16f at the winding start end and the winding end end thereof. With reference to FIGS. 2 and 3, both slide members 17 and 18 for operating the lock members have a recess in the middle portion in the longitudinal direction thereof, and one slide member 17 has a left end and the other slide member 18 has a recess. At the right end thereof, inclined cam surfaces 17a and 18a corresponding to cam surfaces 31a and 31b of a cam portion 31 described later are formed, respectively. At the boundary portion between the inner wall 6b and the shaft hole 8 of the support 6, a guide hole 6c is formed which opens both side surfaces of the inner wall 6b and communicates with the groove portion 8a on the left side of FIG. 3, as shown in FIG. Both slide members 17 and 18 are slidably fitted in the guide hole 6c. The one-way clutch 16b is interposed from the lower outer periphery of the large diameter portion 10b of the swivel shaft 10 to the outer periphery of the lower collar 12, and the upper protrusion 16f is slid through the guide hole 6c.
And the lower projection 16d is relatively engaged with the groove 8a on the left side in FIG. In accordance with this, the one-way clutch 16a is also interposed from the outer periphery of the upper collar 11 to the upper outer periphery of the large diameter portion 10b of the swivel shaft 10, and the upper protrusion 16c has the groove portion 8 on the left side in FIG.
a and the lower projection 16d is engaged with the guide hole.
It relatively engages with the recess of the slide member 17 through 6c. Thus, the pair of one-way clutches 16a, 16b associated with both slide members 17, 18 have one set of protrusions 16c, 16d held in place and the other set of protrusions 16e, 16f pivoting. On the outer periphery of the shaft 10, the shaft 10 moves in the directions shown in FIGS. Therefore, these clutches 16a and 16b can be tightened or loosened. Means B for locking the wheels 1, 1'are as illustrated below. Referring to FIGS. 2, 3, and 5, the inner wall 6b of the support 6
Has a holding hole 19 formed long in the radial direction, and the holding hole 19 is used to make a lock pin 20 and a compression type spring.
21 and 21 are attached to the support 6. That is, both ends of the lock pin 20 penetrating the holding hole 19 of the support inner wall 6b and intervening on the inner surface side of both wheels 1, 1'are disengaged from the respective locking grooves 2 of both wheels 1, 1 '. The spring 21 held freely by the holding hole 19 of the support inner wall 6b presses the lock pin 20 in the direction of engaging with each locking groove 2. The means C for operating the above-described turning axis lock means A and wheel lock means B is as exemplified below. Referring to FIG. 1, FIG. 2, and FIG. 6 to FIG. 8, a pair of fan-shaped operation plates 22 is a locus circle centered on a fulcrum of each operation plate 22 on these plate surfaces. The guide long holes 27 for moving the lock pins formed above, and the three sets having different positions and depths formed on the outer peripheral edge of each of the guide long holes 27 for engaging and holding the lock pins 20. Locking recesses 28, 29, 30
And a cam portion 31 for pushing the lock member formed on the free end portion side of each operation plate 22. In both operation plates 22 arranged between both wheels 1, 1 ′ and the inner wall 6 b of the support body, the fulcrum portion (shaft hole) 25 of these operation plates 22 has the axle 5
It is pierced by and is rotatably supported. The operation plates 22 and the operation lever 24 are connected to each other via a connecting pin 23, and the operation end of the operation lever 24 projects outside the support 6 from the opening window 26 of the support outer wall 6a. . The cam surface of each cam portion 31 on the free end side of the pair of operation plates 22
As shown in FIGS. 10 (a) and (b), 31a and 31b have a substantially planar C-shape corresponding to the cam surfaces 17a and 18a of the two slide members 17 and 18, and both cam surfaces face downward. 31
The distance between a and 31b gradually becomes wider. Therefore,
When these operating plates 22 are assembled in the support 6 as described, these cam surfaces 17a, 18a and cam surfaces 31a, 31b make relative contact. Three sets of locking recesses 28, 29, 30 formed on a pair of operation plates
Satisfies the following condition. The set of locking recesses 28 includes a cam portion 31 (cam surfaces 31a and 31b) and a lock member 16 (one-way clutches 16a and 16b) associated therewith.
When both operation plates 22 that lock the swivel shaft 10 via the and are rotationally displaced to the position where the swivel shaft 10 is unlocked (FIG. 9), the lock pin 20 is engaged in the locking recess 28. It has a portion on the operation plate 22 that can be moved and a depth that allows the lock pin 20 to be disengaged from the locking groove 2 of both wheels 1, 1'as shown in FIG. In the other set of the locking recesses 29, the operation plate 22 is provided with the rotary shaft 10 via the cam portion 31 (cam surfaces 31a, 31b) and the lock member 16 (one-way clutch 16a, 16b) linked thereto. When the lock pin 20 is rotationally displaced to the locking position (Fig. 9), the lock pin 20 can be engaged with the locking recess 29 on the operation plate 22, and the lock is performed as shown in Fig. 5 (a). It has a depth such that the pin 20 can be disengaged from the locking groove 2 of both wheels 1, 1 '. In the remaining set of locking recesses 30, both operation plates 22 lock the swivel shaft 10 via the cam portion 31 (cam surfaces 31a, 31b) and the lock member 16 (one-way clutch 16a, 16b) linked thereto. The position on the operation plate 22 where the lock pin 20 can be engaged with the locking recess 30 when the lock pin 20 is rotationally displaced to the position (Fig. 9) and the lock pin as shown in Fig. 5B. The depth is such that 20 can be engaged with the locking groove 2 of both wheels 1, 1 '. The two-wheel caster illustrated in FIGS. 1 to 10 is operated as follows to obtain each locked state and each unlocked state. When the operation lever 24 is operated and both operation plates 22 are rotationally displaced to a predetermined position as shown in FIGS. 6 and 9, the lock pin 20 fits into the locking recess 28, and FIG. As described above, the slide members 17 and 18 are disengaged from the engagement grooves 2 of the wheels 1 and 1 ', and the slide members 17 and 18 are shifted between the cam surfaces 31a and 31b having a small gap so that the pair of one-way clutches 16a and 16b move to the first position. As shown in Fig. 10 (a), it is released from the outer circumference of the swivel shaft 10. Therefore, in the state of FIGS. 6 and 9, both wheels 1,
Both 1'and swivel shaft 10 are free to rotate. When the operation lever 24 is operated and both operation plates 22 are rotationally displaced to a predetermined position as shown in FIGS. 7 and 9, the lock pin 20 is fitted in the locking recess 29, and FIG. As described above, the slide members 17 and 18 are disengaged from the locking grooves 2 of the wheels 1 and 1 ', and the slide members 17 and 18 are shifted between the cam surfaces 31a and 31b having a wide interval to move the pair of one-way clutches 16a and 16b to the first position. Wrap around the outer circumference of the swivel shaft 10 as shown in Fig. 10 (b). Therefore, in the state of FIGS. 7 and 9, both wheels 1,
1'is free to rotate, but pivot 10 cannot. When the operation lever 24 is operated and both operation plates 22 are rotationally displaced to a predetermined position as shown in FIGS. 8 and 9, the lock pin 20 fits into the locking recess 30 and is then moved to the position shown in FIG. As shown in the above, while relatively engaging with the locking grooves 2 of both wheels 1, 1 ',
Both slide members 17, 18 shift between the cam surfaces 31a, 31b with a wide interval, and a pair of one-way clutches 16a, 16b wind around the outer periphery of the swivel shaft 10 as shown in FIG. Therefore, in the state of FIGS. 8 and 9, both wheels 1,
Neither 1 'nor the pivot 10 can rotate. In the above, in order to make each position of ,, and so on easily recognizable from the outside, it is desirable to give a display symbol such as, for example, to the periphery of the opening window 26 of the support 6.

【The invention's effect】

The twin-wheel caster according to the present invention has the following effects. [Effect 1] The casters can freely travel in the fully unlocked state in which the wheels can be unlocked and the support and the pivot can be unlocked at the same time, and the wheels can be locked and the support and the pivot can be locked together. Casters can be stopped to a complete stop in all locked states where
Further, the caster can be made to run by specifying the traveling direction in the pivot axis locked state in which the wheels are unlocked to restrain the movement of the pivot axis and the support. Therefore,
The functions required for casters, such as safety, maneuverability, and high-speed mobility, will increase and the practicality will increase. [Effect 2] Since the operation plate and the lock operation member related to the operation plate are housed inside the support body, and a part of these does not protrude from the lower part of the caster, the floor surface (ground) while the caster is running. Wheels and pivots are not inadvertently locked due to collisions with obstacles. Therefore, a stable function can be ensured while the casters are traveling.

[Brief description of drawings]

1 to 10 showing an embodiment of a twin-wheel caster according to the present invention, FIG. 1 is a perspective view of the twin-wheel caster with one wheel removed, and FIG. 2 is a twin-wheel caster. Fig. 3 is an exploded perspective view of the whole, Fig. 3 is a side view of a two-wheel caster with a part cut away, and Figs. 4 (a) and (b) are lock release states (front view) of the two-wheel caster. Locked state view (front view), FIG. 5 (a) (b) are wheel lock release state view (side view schematic) and wheel lock state view (side view schematic) of the twin-wheel caster, and FIG. 6 is wheel of the twin-wheel caster FIG. 7 is a swing wheel lock state view of the two-wheel caster (side view), and FIG. 8 is a swing axis wheel lock state view of the two-wheel caster (side view). ), FIG. 9 is a state diagram (side view) of the operating lever corresponding to each state of FIG. 6 to FIG. FIG) is a tenth view (A) and (B) the relationship diagram between pivot locking member and the operating plate cam unit in the pivot-unlocked state, the pivot lock state of the twin wheel type casters (plan view). 1 …… Wheel 1 ′ …… Wheel 2 …… Locking groove 5 …… Axle 6 …… Support 6a …… Outer wall 6b …… Inner wall 6c …… Guide hole 10 …… Swivel axis 16 …… Lock member 16a …… One-way clutch 16b …… One-way clutch 17 …… Slide member 17a …… Cam surface 18 …… Slide member 18a …… Cam surface 19 …… Holding hole 20 …… Lock pin 21 …… Spring 22 …… Operating plate 24… … Operating lever 25 …… fulcrum part 26 …… opening window 27 …… guide slot 28 …… locking recess 29 …… locking recess 30 …… locking recess 31 …… cam part 31a …… cam surface 31b …… Cam surface

Claims (1)

[Claims] 1. An outer wall (6a) whose lower side is open, and an inner wall (6b) protruding from the widthwise intermediate portion of the inner surface of the outer wall.
And an axial hole (8) extending from the upper side to the lower side of the outer wall (6a)
And a pair of caster wheels (1, 1) in which a support (6) having and a locking groove (2) parallel to the rotation axis are circumferentially adjacent and distributed over the entire inner peripheral surface. ′) And a wheel (5) for these wheels, and a swivel shaft (10) for swiveling the casters, and an axle (5) horizontally penetrating the inner wall (6b) of the support (6) While being rotatably supported by the inner wall (6b), the inner wall (6b)
A pair of wheels (1, 1 ') arranged on both sides of b) are mounted on both ends of the axle (5), and the turning shaft (10) is freely rotatable in the shaft hole (8) of the support (6). In the two-wheel type caster mounted on the other parts, other than the above parts, a lock pin (20) for locking the pair of wheels (1, 1 ') and an elastic force are given to the lock pin (20). Spring (21), a pair of operating plates (22) for operating the lock pin (20), an operating lever (24) for these operating plates, and a pair of locking plates for locking the pivot shaft (10). The lock member (16) and a pair of slide members (17, 18) for operating these lock members are included, and both lock members (16) are of a coil winding spring shape having different coil winding directions. One-way clutch (16a, 16b)
The slide members (17, 18) for activating these lock members have a cam surface (17a, 18a) at one end thereof, and the operation plates (22) are The guide long hole (27) for moving the lock pin formed on the locus circle centered on the fulcrum (25) of the and the outside of the guide long hole (27) for engaging and holding the lock pin (20) Three sets of locking recesses (28, 29, 30) formed on the peripheral edge and having different circumferential positions and different radial depths, and both operation plates (2
2) has a cam portion (31) for pushing the lock member formed on the free end side thereof, and both slide members (17,
18) Cam surface (17a, 18a) and corresponding cam surface (31a, 31a)
b) is formed on the cam portions (31) of both operation plates (22), and an opening window (26) for connecting both operation plates (22) and the operation lever (24) is provided on the support. The holding hole (19) for mounting the lock pin (20) and the spring (21) is formed on the outer wall (6a) of the support (6), and is formed on the inner wall (6b) of the support (6). And a guide hole (6) for connecting both operation plates (22) and the shaft hole (8) of the support (6).
c) is formed at the boundary between the support inner wall (6b) and the shaft hole (8), and the inner wall (6b) of the support (6) and both wheels (1, 1 ') Both operation plates (22) arranged between these support points (25)
Is rotatably supported by being penetrated by an axle (5), and both operation plates (22) and an operation lever (24) are connected to each other so that an operation end portion of the operation lever (24) has an outer wall of a support body ( 6a)
Projecting out of the support body (6) through the opening window (26) of the, and penetrating the holding hole (19) of the support body inner wall (6b) and the elongated guide holes (27) of both operation plates (22). Then, both ends of the wheel lock pin (20) intervening on the inner surface side of both wheels (1, 1 ') can be engaged and disengaged with the respective locking grooves (2) of both wheels (1, 1'). Correspondence, and the spring (21) held by the holding hole (19) of the support inner wall (6b) presses the lock pin (20) in the direction of engaging each locking groove (2). And that the swivel shaft (10) is rotatably inserted in the shaft hole (8) of the support (6), and between the shaft hole (8) and the inner and outer peripheral surfaces of the swivel shaft (10). Both slide members (17, 18) in which both lock members (16) are interposed and the end portions having the cam surfaces (31a, 31b) are opposite to each other are guide holes (6c) of the support body (6).
One end and the other end of both lock members (16) are slidably inserted in the inner surface of the shaft hole (8) and the slide members (17, 18) respectively, and Cam surfaces (31a, 31b) on the cam part (31) of the operation plate (22)
And the cam surfaces (17a, 18a) of both slide members (17, 18) face each other so that they can come into relative contact with each other, and both operation plates (22) have an outer peripheral edge of the guide elongated hole (27). Of the three sets of locking recesses (28, 29, 30) having different relative positions in the circumferential direction and different depths in the radial direction, the cam parts (31) and the slide members (17, 18) are When the two operation plates (22) that lock the swivel axis (10) through the interlocking lock members (16) are rotationally displaced to the position where the swivel axis (10) is unlocked, the lock pin (20) To engage the inside of the wheel with the locking groove (2) of both wheels (1, 1 ')
The pair of locking recesses (28) for disengagement from each other are inside the circumferential portion connecting the open ends of the locking grooves (2) and do not overlap with these locking grooves (2), and , Both operation plates (2
In the rotational displacement state of 2), it occupies a position overlapping with the holding hole (19) of the support inner wall (6b), and both of which are linked with the cam portions (31) and the slide members (17, 18). When both operation plates (22) are rotationally displaced through the lock member (16) to a position where the swivel shaft (10) is locked, the lock pin (20) is engaged inside and both wheels (1,
Another set of locking recesses (29) for detaching from the locking groove (2) of 1 ') is inside the circumferential portion connecting the open ends of the locking grooves (2). Do not overlap with the locking groove (2) and occupy a position that overlaps with the holding hole (19) of the support inner wall (6b) in the rotational displacement posture of both operation plates (22), and both cams When the operation plate (22) is rotationally displaced to a position where it locks the swivel shaft (10) through the lock members (16) linked with the part (31) and the slide members (17, 18), the lock pin Engage (20) with the inside of both wheels (1,
The remaining set of locking recesses (30) for engaging the locking grooves (2) of 1 ') has a depth greater than that of the two sets of locking recesses (28, 29). It is positioned so as to overlap the locking groove (2) facing the locking recess (30), and overlaps the holding hole (19) of the support inner wall (6b) in the rotational displacement posture of both operation plates (22). A twin-wheel caster characterized in that it also occupies a position where it engages with each one locking groove (2) of both wheels (1, 1 ').