阅读说明：本技术 一种快速收放三脚架 (Rapid folding and unfolding tripod ) 是由 张磊 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种快速收放三脚架,所述手柄具有操作机构和扭动机构,所述支架与手柄连接,所述的支架包括若干同步张开机构,若干同步张开机构在外力作用下同步转动相同角度；每个支腿与一个同步张开机构连接；每个所述支腿均包括若干节嵌套连接的脚管,且下一节脚管能够嵌套在上一节脚管外部；每个支腿包括：若干关节,所述关节设置在相邻脚管连接处；关节具有关节锁紧装置和防脱结构；关节锁紧装置包括旋转装置和挤压摩擦件；及传动轴,每个支腿内设置若干依次连接的所述传动轴,最上部的传动轴与扭动机构连接。在手柄处做一个动作实现所有关节的同步锁定,再做一个动作实现所有关节的同步解锁。(the invention discloses a rapid retractable tripod, wherein a handle is provided with an operating mechanism and a twisting mechanism, a bracket is connected with the handle and comprises a plurality of synchronous opening mechanisms, and the synchronous opening mechanisms synchronously rotate at the same angle under the action of external force; each support leg is connected with a synchronous opening mechanism; each support leg comprises a plurality of sections of leg tubes which are connected in a nested manner, and the next section of leg tube can be nested outside the previous section of leg tube; each leg comprises: the joints are arranged at the joints of the adjacent foot tubes; the joint is provided with a joint locking device and an anti-falling structure; the joint locking device comprises a rotating device and a squeezing friction piece; and a plurality of transmission shafts which are connected in sequence are arranged in each supporting leg, and the transmission shaft at the uppermost part is connected with the twisting mechanism. And one action is performed at the handle to realize synchronous locking of all the joints, and the other action is performed to realize synchronous unlocking of all the joints.)

1. Receive and release tripod fast, its characterized in that includes:

the handle is provided with an operating mechanism and a twisting mechanism, and the operating mechanism drives the twisting mechanism to generate horizontal torque;

The bracket is connected with the handle and comprises a plurality of synchronous opening mechanisms, and the synchronous opening mechanisms synchronously rotate by the same angle under the action of external force;

Each supporting leg is connected with one synchronous opening mechanism; each support leg comprises a plurality of sections of leg tubes which are connected in a nested manner, and the next section of leg tube can be nested outside the previous section of leg tube; each leg comprises:

The joints are arranged at the joints of the adjacent foot tubes; the joint is provided with a joint locking device and an anti-falling structure; the joint locking device comprises a rotating device and a squeezing friction piece; the twisting mechanism is connected with the rotating device and used for extruding and extruding the friction piece to deform, the extrusion friction piece is arranged between the rotating device and the foot tubes, and the extrusion friction piece extrudes the foot tubes to generate friction force to lock the relative sliding between two adjacent foot tubes after being deformed; the anti-falling structure is arranged outside the joint of the adjacent foot tubes;

The transmission shafts are arranged in each supporting leg and are connected in sequence, the transmission shaft at the uppermost part is connected with the twisting mechanism, and the upper transmission shaft can be nested outside the next section of transmission shaft; the plurality of transmission shafts synchronously rotate to realize synchronous retraction of the plurality of supporting legs of each supporting leg.

2. a rapid retraction tripod according to claim 1,

The operating mechanism of the handle comprises a holder bearing disc, a handle upper cover, a handle outer shell, a handle chassis, an outer shaft and an inner shaft; the inner shaft is fixedly connected with the holder bearing disc and is a fixed part, the outer shaft is sleeved outside the inner shaft, and the outer shaft is fixedly connected with the handle upper cover, the handle chassis and the handle outer shell and is a rotatable part; the handle shell is rotated by hand to drive the twisting mechanism to rotate.

3. A rapid retraction tripod according to claim 1,

The operating mechanism of the handle comprises a holder bearing disc, an elastic piece, a handle shell and a handle bottom shell, the bottom end of the handle bottom shell is fixedly connected to the support, the upper surface of the handle bottom shell is hinged to the bottom end of the grab handle, the upper end of the grab handle is hinged to the grab handle extension rod, and the grab handle extension rod is hinged to the longitudinal axis of the grab handle extension rod and the grab handle push rod; the handle push rod penetrates into the holder bearing disc through the holder bearing disc gap, two nested concentric shafts are arranged in the handle, the inner shaft is fixedly connected to the center of the support, and the outer shaft is sleeved outside the inner shaft; the top end of the outer shaft is fixedly connected with two identical supporting columns, and the supporting columns are fixedly connected with the disc; the middle of the disc is provided with a slideway penetrating through the disc, the two ends of the slideway are round, and the middle part of the slideway is a narrow channel; one end of the grab handle push rod is provided with a sliding part which is connected with a shaft and is arranged on the narrow channel in a sliding way; the elastic piece is arranged on the inner side of the grab handle; the holding and pressing grab handle drives the inner shaft to further drive the twisting mechanism to rotate.

4. a tripod capable of being retracted and extended rapidly as claimed in claim 1, wherein the twisting mechanism comprises a central gear, a plurality of transfer gears and a concentric rotating mechanism, the inner shaft of the handle is fixedly connected with the central gear, the central gear is meshed with the plurality of transfer gears, each transfer gear is connected with a transfer shaft, the transfer shafts extend into the bracket and are connected with the leg transfer shafts through universal couplings, the lower ends of the leg transfer shafts extend into the leg tubes and are connected with the transmission shafts, the transmission shafts extend into the inner rings of the concentric rotating mechanism, and the outer rings of the concentric rotating mechanism are fixedly connected with the inner walls of the lower ends of the corresponding leg tubes; the inner ring of the concentric rotating mechanism is connected with the corresponding rotating device.

5. A tripod capable of being retracted and extended rapidly as claimed in claim 1, wherein the twisting mechanism comprises a plurality of pairs of pulling ropes, a concentric rotating mechanism and a non-circular sliding sleeve, the bottom end of the outer shaft of the handle is fixedly connected with and wound around the plurality of pairs of pulling ropes in a staggered manner, and each pair of pulling ropes passes through the bracket downwards and enters the leg; the outer ring of the concentric rotating mechanism is fixedly connected with the inner wall of the lower end of the corresponding foot tube, the outer ring of the concentric rotating mechanism is provided with two guide rings, and the non-circular sliding sleeve is connected with the inner ring of the concentric rotating mechanism; the transmission shaft stretches into the noncircular sliding sleeve, the end parts of two traction ropes of each pair of traction ropes respectively bypass one guide ring and then are connected with the outer wall of the noncircular sliding sleeve, and the noncircular sliding sleeve is connected with a corresponding rotating device.

6. A rapidly retracting tripod according to claim 4 or 5, wherein said rotating means comprise a disc, the lower end of said drive shaft being fixedly connected to the inner ring of the concentric rotating means; the inner ring of the concentric rotating mechanism extends downwards, and the bottom end of the inner ring is fixedly connected with the disc.

7. A rapid-release tripod according to claim 6, wherein said disc has an arcuate ramp at its upper edge;

The extrusion friction piece is a friction ring which is sleeved outside the disc and the concentric rotating mechanism, the friction ring is a circular ring with a gap, the upper half part of the longitudinal section of the circular ring is trapezoidal, a convex block is arranged on the inner wall of the friction ring, and the lower surface of the convex block is propped against the arc-shaped slope; the inclined plane of the upper half part of the inner wall of the friction ring props against the outer side of the lower end of one leg pipe, and the outer wall of the friction ring is hooped by the inner wall of the next leg pipe; the lower end of the upper pin tube is provided with a square bump which is clamped at the notch of the friction ring.

8. A tripod capable of being retracted and extended rapidly as claimed in claim 6, wherein the pressing friction member is a friction ring, the friction ring is sleeved outside the disc and the concentric rotating mechanism, the friction ring is a ring with a notch, an inner ring is arranged inside the friction ring, and the inner ring is clamped on the upper edge of the disc.

9. A rapid-release tripod according to claim 6, wherein said disc is peripherally connected to a friction-compression element; the extrusion friction piece is a non-circular friction block, the inner wall of the next section of the foot tube can be tightly extruded by the rotation of the friction block, and the inner wall of the foot tube matched with the friction block is of a non-circular structure.

10. A rapid-release tripod according to claim 6, wherein said disc is provided at a lower end thereof with a non-dome block; the extrusion friction piece comprises at least one friction plate, one end of the friction plate is hinged to the lower end of the disc, and the non-circular-top block rotates to extrude the friction plate to be extruded with the inner wall of the next section of pin pipe, so that the joint is locked.

11. A rapid retraction tripod according to claim 4 or 5, wherein said concentric rotation mechanism is a bearing or screw nut arrangement;

The bearing is a sliding bearing or a rolling bearing;

The screw nut structure comprises a nut and a lantern ring with threads, and the nut is in threaded connection with the lantern ring.

12. The quick retracting tripod according to claim 1, wherein the anti-dropping structure comprises an anti-dropping nut, the outer side of the upper end of the next leg tube in the adjacent leg tubes is provided with a thread, the anti-dropping nut is sleeved at the upper end of the next leg tube, and the anti-dropping nut is in threaded connection with the upper end of the leg tube; the inner diameter of the upper end of the anti-falling nut is smaller than the outer diameter of the extrusion friction piece and larger than the outer diameter of the upper section of the pin pipe.

13. A tripod capable of being retracted and extended rapidly as claimed in claim 1, wherein the anti-slip structure comprises an anti-slip screw, a sliding groove is arranged outside the upper leg tube in the adjacent leg tube, and the end of the anti-slip screw passes through the lower leg tube and is arranged in the sliding groove of the upper leg tube.

14. The rapid retracting tripod according to claim 1, wherein the synchronous stretching mechanism comprises a support and bevel gears, the plurality of supports are uniformly distributed at the lower end of the handle, one bevel gear is arranged on each of two sides of each support through a gear base, and the two bevel gears on the same side of two adjacent supports are meshed; the lower end of each gear base is connected with one supporting leg.

Technical Field

the present invention relates to a telescopic tripod for the support of cameras, video cameras, lamps, measuring instruments or other suitable equipment.

Background

The telescopic tripod consists of a plurality of sections of foot tubes, wherein a relevant section between each section of foot tube is used for locking the connection between the two sections of foot tubes, and each joint of the traditional tripod supporting leg needs to be respectively locked and loosened. If each leg consists of 3 leg tubes, 6 joints exist in one tripod. The traditional tripod needs 6 movements to lock 6 joints, and then 6 movements to relax 6 joints. The existing tripod capable of being rapidly retracted and released has two types:

1. The joints are not required to be locked respectively, the eccentric circular supporting legs are rotated by two hands, the supporting legs are locked by mutual extrusion friction of the pipe walls of the upper and lower sections of leg pipes, and the locking mechanism is convenient and quick. However, the leg material is elastic, the rigidity is poor, the locking reliability is poor, the bearing capacity is low, and the three legs need to be locked and unlocked respectively.

a "one-to-three" camera tripod: the bearing performance and stability can reach the level of a common tripod, but the volume and the weight are large, and three supporting legs need to be locked and loosened respectively.

A method for opening and closing three supporting legs at the same angle by using a traditional tripod comprises the following steps: the lower ends of the first section of leg tubes of each leg are connected together by a connecting rod, and the two ends of the connecting rod are hinged.

Disclosure of Invention

In order to solve the problem that an existing tripod cannot be rapidly folded and unfolded, the invention provides a rapid folded and unfolded tripod, which can achieve synchronous locking of all joints by one action at a handle and achieve synchronous unlocking of all joints by the other action.

In order to achieve the purpose, the invention adopts the following technical scheme:

A quick release tripod comprising:

The handle is an operating device of a tripod. The handle is provided with an operating mechanism and a twisting mechanism, and the operating mechanism drives the twisting mechanism to generate torque in the horizontal direction;

The support is a device for connecting the handle and the support leg. The bracket is connected with the handle and comprises a plurality of synchronous opening mechanisms, and the synchronous opening mechanisms synchronously rotate by the same angle under the action of external force;

and a plurality of legs, the legs being the support portion of the tripod. Each support leg is connected with a synchronous opening mechanism; each support leg comprises a plurality of sections of leg tubes which are connected in a nested manner, and the next section of leg tube can be nested outside the previous section of leg tube; the uppermost leg tube is called a first section leg tube, the leg tube below the uppermost leg tube is called a second section leg tube, and the rest is done in the same way; each leg comprises:

The joints are mechanisms for connecting two adjacent foot tubes; the joint is provided with a joint locking device and an anti-falling structure; the joint locking device comprises a rotating device and a squeezing friction piece; the twisting mechanism is connected with the rotating device and is used for extruding and extruding the friction piece to deform, the extrusion friction piece is arranged between the rotating device and the foot tubes, and the extrusion friction piece extrudes the foot tubes to generate friction force after being deformed, so that two adjacent foot tubes cannot slide relatively, namely a locking joint; when the foot tube moves reversely, the pressure between the extrusion friction piece and the foot tube is released, and two adjacent foot tubes can slide relatively, which is called as a loosening (or unlocking) joint; the joint between the first joint leg tube and the second joint leg tube is called a first joint, the joint between the second joint leg tube and the third joint leg tube is called a second joint, and the rest can be done in the same way; the anti-falling structure is arranged outside the joint of the adjacent foot tubes;

The transmission shafts are arranged in each supporting leg and are connected in sequence, the transmission shaft at the uppermost part is connected with the twisting mechanism, and the upper transmission shaft can be nested outside the next section of transmission shaft; the plurality of transmission shafts synchronously rotate to realize synchronous retraction of the plurality of supporting legs of each supporting leg.

As a further improvement of the invention, the operating mechanism of the handle comprises a holder bearing disc, a handle upper cover, a handle outer shell, a handle chassis, an outer shaft and an inner shaft; the inner shaft is fixedly connected with the holder bearing disc and is a fixed part, the outer shaft is sleeved outside the inner shaft, and the outer shaft is fixedly connected with the handle upper cover, the handle chassis and the handle outer shell and is a rotatable part; the handle shell is rotated by hand to drive the twisting mechanism to rotate.

As a further improvement of the invention, the operating mechanism of the handle comprises a holder bearing disc, an elastic part, a handle shell and a handle bottom shell, the bottom end of the handle bottom shell is fixedly connected to the support, the upper surface of the handle bottom shell is hinged with the bottom end of the grab handle, the upper end of the grab handle is hinged with the grab handle extension rod, and the grab handle extension rod is hinged with the longitudinal axis of the grab handle extension rod and the grab handle push rod; the handle push rod penetrates into the holder bearing disc through the holder bearing disc gap, two nested concentric shafts are arranged in the handle, the inner shaft is fixedly connected to the center of the support, and the outer shaft is sleeved outside the inner shaft; the top end of the outer shaft is fixedly connected with two identical supporting columns, and the supporting columns are fixedly connected with the disc; the middle of the disc is provided with a slideway penetrating through the disc, the two ends of the slideway are round, and the middle part of the slideway is a narrow channel; one end of the grab handle push rod is provided with a sliding part which is connected with a shaft and is arranged on the narrow channel in a sliding way; the elastic piece is arranged on the inner side of the grab handle and can be a spring piece or a pressure spring; the holding and pressing grab handle drives the inner shaft to further drive the twisting mechanism to rotate.

As a further improvement of the invention, the twisting mechanism comprises a central gear, a plurality of transfer gears and a concentric rotating mechanism, an inner shaft of the handle is fixedly connected with the central gear, the plurality of transfer gears are arranged at the bottom of a chassis of the handle, the central gear is engaged with the plurality of transfer gears, each transfer gear is connected with a transfer shaft, the transfer shafts extend into the bracket and are connected with the leg transfer shafts through universal couplings, the lower ends of the leg transfer shafts extend into the foot tubes and are connected with the transmission shafts, the transmission shafts extend into inner rings of the concentric rotating mechanism, and outer rings of the concentric rotating mechanism are fixedly connected with the inner walls of the lower ends of the corresponding foot tubes; the inner ring of the concentric rotating mechanism is connected with the corresponding rotating device.

As a further improvement of the invention, the twisting mechanism comprises a plurality of pairs of traction ropes, a concentric rotating mechanism and a non-circular sliding sleeve, the bottom end of the outer shaft of the handle is fixedly connected with and wound with the plurality of pairs of traction ropes in a staggered manner, and each pair of traction ropes downwards penetrate through the bracket and enter the supporting leg; the outer ring of the concentric rotating mechanism is fixedly connected with the inner wall of the lower end of the corresponding foot tube, the outer ring of the concentric rotating mechanism is provided with two guide rings, and the non-circular sliding sleeve is connected with the inner ring of the concentric rotating mechanism; the transmission shaft stretches into the noncircular sliding sleeve, the end parts of two traction ropes of each pair of traction ropes respectively bypass one guide ring and then are connected with the outer wall of the noncircular sliding sleeve, and the noncircular sliding sleeve is connected with a corresponding rotating device.

as a further improvement of the invention, the rotating device comprises a disc, and the lower end of the transmission shaft is fixedly connected with an inner ring of the concentric rotating mechanism; the inner ring of the concentric rotating mechanism extends downwards, and the bottom end of the inner ring is fixedly connected with the disc.

as a further improvement of the invention, the extrusion friction piece is a friction ring, the friction ring is sleeved outside the disc and the concentric rotating mechanism, the friction ring is a circular ring with a gap, the upper half part of the longitudinal section of the circular ring is trapezoidal, a convex block is arranged on the inner wall of the friction ring, and the lower surface of the convex block is propped against the arc-shaped slope; the inclined plane of the upper half part of the inner wall of the friction ring props against the outer side of the lower end of one leg pipe, and the outer wall of the friction ring is hooped by the inner wall of the next leg pipe; the lower end of the upper pin tube is provided with a square bump which is clamped at the notch of the friction ring.

as a further improvement of the invention, the extrusion friction piece is a friction ring, the friction ring is sleeved outside the disc and the concentric rotating mechanism, the friction ring is a circular ring with a notch, a spiral inner convex ring is arranged inside the friction ring, and the inner convex ring is clamped on the upper edge of the disc.

As a further improvement of the invention, the periphery of the disc is connected with a squeezing friction piece; the extrusion friction piece is a non-circular friction block, and the inner wall of the next section of pin pipe can be tightly extruded by the rotation of the friction block. The inner wall of the foot tube matched with the friction block is also non-circular.

as a further improvement of the invention, the lower end of the disc is provided with a non-dome block; the extrusion friction piece comprises at least one friction plate, one end of the friction plate is hinged to the lower end of the disc, and the non-circular-top block rotates to extrude the friction plate to be extruded with the inner wall of the next section of pin pipe, so that the joint is locked.

As a further improvement of the invention, the concentric rotating mechanism is a bearing or screw nut structure; the bearing is a sliding bearing or a rolling bearing and has the same effect; the screw nut structure comprises a nut and a lantern ring with threads, and the nut is in threaded connection with the lantern ring.

As a further improvement of the invention, the anti-falling structure comprises an anti-falling nut, wherein in the adjacent leg tubes, the outer side of the upper end of the next leg tube is provided with a thread, the anti-falling nut is sleeved at the upper end of the next leg tube and is in threaded connection with the upper end of the leg tube; the inner diameter of the upper end of the anti-falling nut is smaller than the outer diameter of the extrusion friction piece and larger than the outer diameter of the upper section of the pin pipe.

as a further improvement of the invention, the anti-drop structure comprises an anti-drop screw, a sliding groove is arranged outside the upper section of the adjacent leg tube, and the end part of the anti-drop screw penetrates through the lower section of the leg tube and is arranged in the sliding groove of the upper section of the leg tube.

as a further improvement of the invention, the synchronous opening mechanism comprises supports and bevel gears, wherein a plurality of the supports are uniformly distributed at the lower end of the handle, two sides of each support are provided with one bevel gear through a gear base, and two bevel gears at the same side of two adjacent supports are meshed; the lower end of each gear base is connected with one supporting leg.

Compared with the prior art, the invention has the following advantages:

A handle is arranged above the connecting position of the three supporting legs, namely the top of the tripod, and by holding or rotating the handle, synchronous unlocking of all joints of the three supporting legs can be completed by one action, and synchronous locking of all joints of the three supporting legs can be completed by another action. The lower ends of the holding and pressing handle and the rotating handle are both rotatable shafts, the holding and pressing motion of the holding and pressing handle is converted into shaft rotating motion at the lower end, namely, the power output modes of the holding and pressing handle and the rotating handle are the same. And one action is performed on the handle to realize synchronous locking of all the joints, and the other action is performed to realize synchronous unlocking of all the joints. If one tripod is provided with three sections of foot tubes, the action number can be reduced to 1/6, so that the rapid folding and unfolding of the multiple sections of foot tubes are realized, and the folding and unfolding operation of the tripod is greatly simplified.

Further, the transmission mechanism between the handle and the first joint is a gear, a connecting rod, a universal coupling or a steel wire rope. The transmission mechanism in the supporting leg is two steel wire ropes or transmission shafts.

Further, the synchronous locking or unlocking of the second joint is realized by the linkage of a non-circular transmission shaft passing through a non-circular pipe in the center of the first joint.

Further, the locking joint (i.e. limiting the relative sliding between the two legs) is realized by the rotating device at the joint driving the friction device to press the legs.

Further, the implementation mode that three supporting legs are opened synchronously is as follows: a pair of conical gears is arranged at the upper end of each pin, the three pairs of conical gears are meshed with each other, and when one supporting leg is held by two hands respectively to be opened at a certain angle, the third supporting leg is synchronously opened at the same angle through the transmission of the gears.

Drawings

fig. 1 is an overall external view of embodiment 1 of the present invention.

Fig. 2 is an external view and an internal view of a handle portion of embodiment 1 of the present invention.

fig. 3 is an external view and an internal view of a stent of embodiment 1 of the present invention.

Fig. 4 is an external view and an internal view of the first joint of the single-support leg of embodiment 1 of the present invention.

Fig. 5 is a view of a friction ring according to embodiment 1 of the present invention.

FIG. 6 is a longitudinal sectional view of the first joint of the single leg of example 1 of the present invention.

figure 7 is an external view and an internal view of a second joint of a single leg according to embodiment 1 of the present invention.

fig. 8 is an overall external view of embodiment 2 of the present invention.

Fig. 9 is an external view and an internal view of a handle portion of embodiment 2 of the present invention.

Fig. 10 is an external view and an internal view of a pan/tilt head carrier plate according to embodiment 2 of the present invention.

Fig. 11 is a side view showing the relationship between the handle push rod and the disk in embodiment 2 of the present invention.

Fig. 12 is an external view and an internal view of a stent of embodiment 2 of the present invention.

figure 13 is an external view and an internal view of the first joint of the single leg of embodiment 2 of the present invention.

Fig. 14 is a view of a friction ring of a single leg of embodiment 2 of the present invention.

figure 15 is a longitudinal cross-sectional view of the first joint of a single leg of example 2 of the present invention.

Figure 16 is an external view and an internal view of a second joint of a single leg according to embodiment 2 of the present invention.

Fig. 17 is an overall external view of embodiment 3 of the present invention.

Fig. 18 is an external view and an internal view of a handle and a bracket according to embodiment 3 of the present invention.

figure 19 is an external and internal view of the first joint of a single leg of embodiment 3 of the present invention.

Fig. 20 is a longitudinal sectional view of a first joint according to embodiment 3 of the present invention.

fig. 21 is a top view showing the positional structure of each component of the first joint according to embodiment 3 of the present invention.

Figure 22 is an external and internal view of the second joint of the single leg of embodiment 3 of the present invention.

Fig. 23 is an overall external view of embodiment 4 of the present invention.

fig. 24 is an external view and an internal view of a handle and a holder according to embodiment 4 of the present invention.

figure 25 is an external and internal view of the first joint of the single leg of embodiment 4 of the present invention.

Fig. 26 is a bottom view of the locking mechanism of the first joint according to embodiment 4 of the present invention.

figure 27 is an external and internal view of the second joint of the single leg of embodiment 4 of the present invention.

Wherein, 4 embodiments are ABCD respectively, and the structure of each tripod comprises four parts: 1 handle, 2 supports, 3 supporting legs and 4 joints.

The handle, the bracket, the legs and the joints of the embodiment 1 are respectively A1, A2, A3 and A4, the parts of the handle are marked as A11-A19, the parts of the bracket are marked as A21-A28, the parts of the legs are marked as A31-A38, and the parts of the joints are marked as A41-A47. A1, a handle, a2, a bracket, A3, a leg, A4 joint, a11, a pan-tilt bearing disc, a12, a screw, a13, a pan-tilt bearing disc notch, a14, an inner shaft, a15, a handle upper cover, a16, a handle upper cover protrusion, a17, an outer shaft, a18, a handle chassis, a19, a handle housing, a21, a holder, a22, a gear base, a23, a bevel gear, a24, a half shaft, a25, a central gear, a26, a transfer gear, a27, a bracket transfer shaft, a28, universal coupling, a31, a first leg tube, a32, a second leg tube, a33, a third leg tube, a34, a foot, a35, leg transfer shaft, a36, first transfer shaft, a37, a second transfer shaft, a38, a square bottom ends of first and second leg tubes, a41, a square bottom end of a41, a friction protrusion, 41, a friction ring, 41, and a 41.