CN215015389U

CN215015389U - Adjustable folding chair

Info

Publication number: CN215015389U
Application number: CN202120275957.2U
Authority: CN
Inventors: 朱晓辉; 张帆
Original assignee: Zhejiang Sunshine Leisure Products Co ltd
Current assignee: Zhejiang Sunshine Leisure Products Co ltd
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2021-12-07
Anticipated expiration: 2031-01-29

Abstract

The utility model discloses an adjustable folding chair, which comprises a chair main body, a first folding mechanism and a second folding mechanism; a first folding mechanism is arranged between two backrest rods of the chair main body, the upper end of the first folding mechanism is hinged with the upper section of the backrest rod, and the lower end of the first folding mechanism is hinged with the lower end of the backrest rod through a short rod; two ends of the second folding mechanism are respectively hinged with the front ends of the two bottom rods and the lower ends of the two front foot tubes of the chair main body. The utility model discloses can effectively reduce folding back volume, improve folding effect.

Description

Adjustable folding chair

Technical Field

The utility model relates to a technical field of folding chair especially relates to an adjustable folding chair.

Background

Folding chairs are widely used due to their small footprint and convenience. The utility model patent with application number CN200420027277.5, entitled "hard armrest adjustable folding chair", discloses a chair main body structure composed of a backrest tube (i.e., a backrest rod), a seat frame tube (i.e., a bottom rod), a front leg (i.e., a front leg tube), a rear leg (i.e., a rear leg tube), a hard armrest (i.e., an armrest piece), and the like; the rear cross pipe, the telescopic inner pipe, the telescopic outer pipe and the like are a first folding mechanism; the front cross pipe and the like are a second folding mechanism; the upper end of the back cross pipe is hinged with the front foot pipe, the lower end is hinged with the back foot pipe, the backrest pipe is hinged on the telescopic outer pipe sleeve separately, the upper end of the front foot pipe is connected with the telescopic pipe, and the folding chair has the following defects: firstly, the backrest tube is separately hinged on the telescopic outer tube sleeve, the backrest has no outward supporting force, and when a person sits on the seat, the backrest tube is easy to recess inwards, so that the comfort degree is affected; secondly, the product is folded by means of the extension of the telescopic pipe, and the folding size of the product is larger.

The utility model discloses a utility model "adjustable folding chair of back" with application number cn201020641647.x, which discloses that the back and the seat frame (namely, back rod and bottom rod), the front leg (namely, front leg tube), the rear leg (namely, rear leg tube), the armrest (namely, armrest piece) and the like which are hinged with each other form the main structure of the chair; the adjusting support frame, the sliding rod and the like form a first folding mechanism; a second folding mechanism is a stay bar (namely a front cross pipe) which is crossed in an X shape and hinged at the middle part; the seat frame and the backrest are supported by an X-shaped adjusting support frame and X-shaped crossed support rods, the adjusting support frame is fixed by a cross brace, the upper end of the adjusting support frame is sleeved on the slide rod, and the lower end of the adjusting support frame is hinged with the rear foot tube, so that the folding chair has the following defects: firstly, extra stay bars are needed for realizing the support, and the cost is increased; secondly, the backrest angle is adjusted, namely the backrest is folded integrally, and the backrest angle cannot be freely adjusted according to self conditions after a person sits on the seat.

The utility model patent with application number CN202020206615.0 discloses a folding chair, which discloses a main structure of a chair composed of a backrest rod, a seat rod (i.e. a bottom rod), a front leg (i.e. a front leg tube), a rear leg (i.e. a rear leg tube), a handrail (i.e. a handrail member), etc.; the rear connecting rod (namely the rear cross pipe), the sliding sleeve, the guide rod and the like form a first folding mechanism; the front connecting rods (namely front cross pipes) which are arranged in a cross mode are used as second folding mechanisms; the rear end of the chair surface rod of the folding chair is hinged with the lower end of the backrest rod through a transition rod, the upper end of the limiting structure is movable on a guide rod at the upper end of the backrest rod, the lower end of the limiting structure is hinged with the rear end of the chair surface rod, and folding and unfolding are realized through the hinging; such folding chairs have the following drawbacks: firstly, a sliding sleeve needs to be arranged on the limiting structure to be matched with the guide rod for movement, so that the number of accessories is large, and the structure is complex; secondly, the limiting structure can only move up and down along the guide rod of the backrest rod, and because the distance exists between the limiting structure after the guide rod is folded and the backrest rod, the size is larger after the backrest rod is folded, and the backrest rod is inconvenient to store; thirdly, the lower end of the limiting structure is hinged with the rear end of the chair surface rod, so that the limiting structure and the backrest rod are not on the same horizontal plane, the supporting effect on people cannot be well achieved, and the overall comfort level is affected; and the transition rod is arranged at the lower end of the back rest rod and the rear section of the seat rod, and even if the chair is completely folded, the back rest rod and the seat rod still have a certain included angle, so that the folded chair has larger volume and poor folding effect.

In summary, the two backrest rods arranged in parallel, the bottom rod connected with the backrest rods, the armrest piece, the front foot tube and the rear foot tube which are hinged form the main body structure of the folding chair; the rear cross pipe and the like form a first folding mechanism; the front cross pipe and the like form a second folding mechanism; as can be seen from the three patents, the folding mechanisms are substantially the same, but the specific connection manner between the folding mechanism and the main structure of the chair is different, so that the problems of large volume and poor folding effect after folding exist in the existing folding chair; in view of the above, the present inventors have studied specifically on the structure of a folding chair, and developed and designed an adjustable folding chair that can effectively reduce the folded volume and improve the folding effect.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an adjustable folding chair to effectively reduce folding back volume, improve folding effect.

In order to realize the purpose, the utility model discloses a technical scheme as follows:

an adjustable folding chair comprises a chair main body, a first folding mechanism and a second folding mechanism; a first folding mechanism is arranged between two backrest rods of the chair main body, the upper end of the first folding mechanism is hinged with the upper section of the backrest rod, and the lower end of the first folding mechanism is hinged with the lower end of the backrest rod through a short rod; two ends of the second folding mechanism are respectively hinged with the front ends of the two bottom rods and the lower ends of the two front foot tubes of the chair main body.

The U-shaped pipe is sleeved on the upper section of the backrest rod, the top surface of the U-shaped pipe is hinged to the upper end of the first folding mechanism through a bolt, and the first folding mechanism can be hinged to the upper section of the backrest rod through the U-shaped pipe.

The first folding mechanism comprises two crossed back cross pipes and a back support piece, the upper ends of the two back cross pipes are hinged with the upper section of the back rod, the middle parts of the two back cross pipes are hinged, the back support piece is used for connecting the upper sections of the two back cross pipes, and the two ends of the short rod are respectively hinged with the lower ends of the back cross pipes and the lower end of the back rod.

The back support piece comprises a first support rod, a second support rod and a support clamping piece, the first support rod and the second support rod are respectively connected with the upper sections of the two back cross pipes, the support clamping piece is arranged between the first support rod and the second support rod, and the first support rod and the second support rod are controlled to be away from and close to each other through the support clamping piece.

The support fastener is one end open-ended body, and the mounting hole has been seted up to the body side, and first bracing piece is inserted and is established in the opening, and the second bracing piece passes through the mounting hole and supports fastener swing joint, supports the fastener and still is equipped with the stopper for the home range of spacing second bracing piece.

The tail end of the back support rod is connected with the rear end of the bottom rod through a connecting piece, the connecting piece main body is L-shaped, one side of the connecting piece is fixedly connected with the back support rod, and the other side of the connecting piece is movably connected with the bottom rod.

Two front foot tubes of the chair main body are hinged with the middle section of the bottom rod, two rear foot tubes of the chair main body are hinged with the tail end of the bottom rod through a rotating piece, the upper ends of the front foot tubes are hinged with the upper ends of the rear foot tubes and supported below two armrest pieces of the chair main body, and the rear ends of the armrest pieces are hinged with the lower end of the backrest rod.

The handrail piece includes wooden handrail and fender position spare, keeps off the position spare and is located wooden handrail below, keeps off and is equipped with a plurality of constant head tanks on the position spare, and the articulated shaft joint of preceding, back foot pipe is in the constant head tank, through adjusting the angle of articulated shaft position in order to adjust back pole and sill bar in the constant head tank.

The second folding mechanism comprises two front cross pipes which are crossed, the middle parts of the two front cross pipes are hinged, and two ends of each front cross pipe are connected with the bottom rod and the front leg pipe through hinge pieces respectively.

The articulated piece is set up for the L type, and articulated piece one side is fixed on the front foot pipe, and articulated piece opposite side passes through the bolt and hinges with preceding cross tube.

After the scheme is adopted, compared with the prior art, the utility model, have following advantage: the upper end of the first folding mechanism is hinged with the upper section of the backrest rod, a sliding sleeve and a guide rod component are not required to be arranged, the structure is simple, materials are saved, and the cost is reduced; the two backrest rods are connected with the first folding mechanism through the movable piece and the short rod, the short rod is attached to the backrest rods after folding, the distance between the backrest rods and the first folding mechanism is small, the volume is greatly reduced after folding, and the folding backrest is convenient to store; the lower end of the first folding mechanism is connected to the lower end of the backrest rod through the short rod, the first folding mechanism and the short rod form a four-connecting-rod assembly, the four-connecting-rod assembly is favorable for supporting a chair seat, the backrest does not deform inwards in a concave mode, a good supporting effect can be achieved for people, and the overall comfort level is improved; and fourthly, the four-connecting-rod assembly in front of the two back rest rods is also beneficial to better fit between the back rest rods and the bottom rod after being folded, and the folded back chair has smaller volume and better folding effect.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Drawings

FIG. 1 is a perspective view of the adjustable folding chair of the present invention in an unfolded state;

FIG. 2 is a perspective view of the adjustable folding chair of the present invention in a folded state;

FIG. 3 is a perspective view of the adjustable folding chair of the present invention fully folded;

fig. 4 is a schematic view of a first folding mechanism of the present invention;

figure 5 is a schematic view of the back support of the present invention;

description of reference numerals:

a chair body 1, a backrest rod 11, a bottom rod 12, an armrest piece 13, a wooden armrest 131, a gear piece 132, a positioning groove 133, a front foot tube 14 and a rear foot tube 15; a rotating member 16, a connecting member 17; a hinge shaft 18;

the folding device comprises a first folding mechanism 2, a rear cross pipe 21, a back support part 22, a first support rod 221, a second support rod 222, a support clamping part 223, a U-shaped pipe 23, a mounting hole 224, a limiting block 225 and a foot pad 226;

the second folding mechanism 3, the front cross tube 31, the hinge pieces 32,

a short bar 4.

Detailed Description

As shown in fig. 1 to 5, the adjustable folding chair disclosed in the present invention comprises a chair body 1, a first folding mechanism 2 and a second folding mechanism 3; the chair body 1 comprises two backrest rods 11 arranged in parallel, a bottom rod 12 connected with the backrest rods 11, an armrest 13, a front foot pipe 14 and a rear foot pipe 15 which are hinged, wherein a sitting component can be placed on the bottom rod 12, and a backrest component is placed between the backrest rods 11; a first folding mechanism 2 is arranged between two backrest rods 11 which are arranged in parallel, the upper end of the first folding mechanism is hinged with the upper section of the backrest rod 11, and the lower end of the first folding mechanism 2 is hinged with the lower end of the backrest rod 11 through a short rod 4; the two ends of the second folding mechanism 3 are respectively hinged with the front ends of the two bottom rods 12 and the lower ends of the two front foot tubes 14. Thus, one end of the first folding mechanism 2 is connected with the backrest rod 11 in a hinged mode, and replaces the traditional guide rod and sliding sleeve assembly, so that the number of the assemblies is reduced, the structure is simple, the material is saved, and the cost is reduced; the distance between the backrest rod 11 and the first folding mechanism 2 is smaller, and the volume is greatly reduced after folding, so that the folding is convenient to store; the other end of the first folding mechanism 2 is hinged with the lower end of the backrest rod 11 through the short rod 4, the first folding mechanism 2 and the two short rods 4 form a four-connecting-rod assembly, the supporting effect of the backrest can be improved by adopting the four-connecting-rod assembly, the backrest is not sunken and deformed inwards, and the overall comfort level is improved; and the folded back rest rod 11 and the folded bottom rod 12 can be well jointed, and the folded back rest has smaller volume and better folding effect.

The first folding mechanism 2 comprises two criss-cross back cross pipes 21 and a back support piece 22, the upper ends of the two back cross pipes 21 are hinged with the upper section of the back support rod 11, the middle parts of the two back cross pipes 21 are hinged, the upper section of the back support rod 11 is sleeved with a U-shaped pipe 23, the top surface of the U-shaped pipe 23 is hinged with the upper ends of the two back cross pipes 21 through bolts, so that the first folding mechanism 2 can be hinged with the upper section of the back support rod 11 through the U-shaped pipe 23, and the structure is simple; the other ends of the two back cross pipes 21 are hinged with the lower end of the backrest rod 11 through the short rods 4, the two back cross pipes 21 and the two short rods 4 form a four-connecting-rod assembly, the four-connecting-rod assembly is beneficial to supporting the chair surface and enabling the folded backrest rod to be well attached to the bottom rod, and the folded volume is small; in order to ensure the folding effect, the back support member 22 is arranged between the upper sections of the two back cross tubes 21, the back support member 22 comprises a first support rod 221, a second support rod 222 and a support clamping piece 223, the first support rod 221 and the second support rod 222 are respectively connected with the upper sections of the two back cross tubes 21, the support clamping piece 223 is arranged between the first support rod 221 and the second support rod 222, and the first support rod 221 and the second support rod 222 are controlled to be away from and close to each other through the support clamping piece 223. Support fastener 223 is one end open-ended body, and mounting hole 224 has been seted up to the body side, and first support 221 is inserted and is established in the opening, and second bracing piece 222 passes through mounting hole 224 and supports fastener 223 swing joint, supports fastener 223 top and still is equipped with stopper 225 for the home range of spacing second bracing piece 222. When the folding chair is unfolded, the two back cross pipes 21 are arranged in an X shape, the distance between the two back rest rods 11 is farthest, and the short rods 4 are horizontally placed; the first support rod 221, the support clamping piece 223 and the second support rod 222 tend to be in a straight shape, and the limiting block 225 abuts against the second support rod 222, so that the second support rod 222 cannot move continuously, and the second support rod 222 is limited; when the folding chair is folded, the two back cross pipes 21 gradually approach, and the short rods 4 gradually incline downwards; the second support rod 222 rotates around the mounting hole 224, and gradually approaches the first support rod 221 until the first support rod 221 and the second support rod 222 are attached to each other.

In order to ensure the stable folding of the folding chair, two front foot tubes 14 are hinged with the middle section of a bottom rod 12, two rear foot tubes 15 are hinged with the tail end of the bottom rod 12 through a rotating piece 16, one end of the rotating piece 16 is hinged with the tail end of the bottom rod 12 through a bolt, the other end of the rotating piece 16 is hinged with the upper end of the rear foot tube 15, the upper end of the front foot tube 14 is hinged with the upper end of the rear foot tube 15 and is supported below two handrail pieces 13, the rear end of the handrail piece 13 is hinged with the lower end of a back rod 11, foot pads 26 can be arranged on the ground surfaces of the tail ends of the front foot tube 14 and the rear foot tube 15, in other embodiments, the front foot tube and the rear foot tube can also be provided with rollers or wear-resistant sleeves and the like, which are not listed herein; when the folding chair is unfolded, the rear end of the front foot tube 14 is far away from the rear end of the rear foot tube 15, the front foot tube and the rear foot tube are in an A shape, the rotating piece 16 tends to be attached to the rear foot tube 15, when the folding chair is folded, the front foot tube and the rear foot tube are close to each other, and the rotating piece 16 moves downwards along a hinged point hinged to the rear foot tube.

In order to make the folded volume smaller, the tail end of the back-rest rod 11 is connected with the rear end of the bottom rod 12 through a connecting piece 17, the main body of the connecting piece 17 is L-shaped, one side of the connecting piece 17 is fixedly connected with the back-rest rod 11, and the other side of the connecting piece 17 is movably connected with the bottom rod 12; when the folding chair is unfolded, the tail end of the backrest rod 11 is abutted against the rear end of the bottom rod 12, the backrest rod 11 and the bottom rod 12 tend to form an angle of 90 degrees, when the folding chair is folded, the tail end of the backrest rod 11 and the rear end of the bottom rod 12 are close to each other, and the angle between the backrest rod 11 and the bottom rod 12 gradually decreases until the backrest rod 11 and the bottom rod 12 tend to be attached. In other embodiments, the connection between the back-rest rod 11 and the bottom rod 12 can be achieved by connecting the two bottom rods 12 at the joints of the front and rear leg tubes, respectively, and hinging the front leg tube 14 with the back-rest rod 11, but the connection piece in this embodiment can ensure a smaller volume after folding.

In order to adjust the angle between the backrest rod 11 and the bottom rod 12 conveniently, and facilitate the sitting of a person on the folding chair according to the habit of the person, the armrest part 13 comprises a wooden armrest 131 and a blocking part 132, the blocking part 132 is positioned below the wooden armrest 131, the blocking part 132 is provided with a plurality of positioning grooves 133, hinge shafts 18 of the front foot tube and the rear foot tube are clamped in the positioning grooves 133, and the angle between the backrest rod 11 and the bottom rod 12 is adjusted by adjusting the positions of the hinge shafts 18 in the positioning grooves 133; taking the state that the backrest rod 11 and the bottom rod 12 tend to be at 90 degrees as a first unfolding angle, enabling a person to be in a normal sitting posture on the folding chair, moving the position of the hinge shaft 18 in the positioning groove 133 to enable the backrest rod 11 to incline downwards, and taking the state that the backrest rod 11 and the bottom rod 12 tend to be at 180 degrees as a second unfolding angle, wherein at the moment, the person is in a backward leaning sitting posture on the folding chair; the position of the hinge shaft 18 in the positioning slot can be continuously adjusted to adjust the position of the person on the folding chair, and in other embodiments, the connection mode of the front and rear foot tubes and the armrest piece 13 can also adopt a damping mechanism or a positioning pin structure, which is not listed here.

In order to ensure the support of the front end of the bottom rod 12, two ends of the second folding mechanism 3 are respectively hinged with the front end of the bottom rod 12 and the front foot tube 14, the second folding mechanism 3 comprises two front cross tubes 31 which are crossed, the middle parts of the two front cross tubes 31 are hinged, two ends of each front cross tube 31 are respectively connected with the bottom rod 12 and the front foot tube 14 through a hinge sheet 32, furthermore, the hinge sheet 32 is arranged in an L shape, one side of the hinge sheet 32 is fixed on the front foot tube 14, and the other side of the hinge sheet 32 is hinged with the front cross tube 31 through a bolt; in other embodiments, the front cross tube 31 can also be directly connected to the bottom rail 12 and the front leg 14 without the hinge plate 32, but the embodiment uses the hinge plate 32 to facilitate assembly. When the folding chair is unfolded, the two front cross pipes 31 are arranged in an X shape, and when the folding chair is folded, the two front cross pipes 31 gradually approach.

When the folding chair is unfolded, the two back cross pipes 21 are arranged in an X shape, the short rod 4 is in a horizontal state, the first support rod 221, the support clamping piece 223 and the second support rod 222 tend to be in a straight shape, and a backrest part can be placed between the two backrest rods 11 to support the back of a person; the front leg tube 14 and the rear leg tube 15 are in an A shape, the two front cross tubes 31 are in an X shape, and a sitting part can be placed between the two bottom rods 12; when the angle between the backrest rod 11 and the bottom rod 12 tends to be 90 degrees and is a first unfolding angle, a person takes a normal sitting posture on the folding chair; at this time, the angle between the backrest rod 11 and the bottom rod 12 can be adjusted by adjusting the positions of the front and rear foot tube articulated shafts 18 in the positioning grooves 133, so as to adjust the position of a person on the folding chair; the state that the backrest rod 11 and the bottom rod 12 tend to form 180 degrees is a second unfolding angle, and a person takes a backward leaning sitting posture on the folding chair.

When the folding chair is folded, firstly, the angle between the backrest rod 11 and the bottom rod 12 is adjusted through the armrest piece 13, so that the backrest rod 11 and the bottom rod 12 tend to form an angle of 90 degrees and are positioned at a first unfolding angle; secondly, the two backrest tubes 11 are grasped to be close to each other, the two rear cross tubes 21 are gradually close to each other, and the short rods 4 are gradually inclined downwards; the second support rod 222 rotates around the mounting hole 224 and gradually approaches the first support rod 221; the two front cross tubes 31 are gradually close to each other, the front foot tube 14 and the rear foot tube 15 are mutually close to each other, the rotating piece 16 moves downwards along a hinge point hinged with the rear foot tube, the tail end of the backrest rod 11 is mutually close to the rear end of the bottom rod 12, and the angle between the backrest rod 11 and the bottom rod 12 is gradually reduced until the backrest rod 11 and the bottom rod 12 tend to be attached; the whole folding chair is folded, has small volume and good folding effect, and can be conveniently moved.

The above is only the preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and the present invention is modified by this concept, and all shall belong to the act of infringing the protection scope of the present invention.

Claims

1. An adjustable folding chair comprises a chair main body, a first folding mechanism and a second folding mechanism; the method is characterized in that: a first folding mechanism is arranged between two backrest rods of the chair main body, the upper end of the first folding mechanism is hinged with the upper section of the backrest rod, and the lower end of the first folding mechanism is hinged with the lower end of the backrest rod through a short rod; two ends of the second folding mechanism are respectively hinged with the front ends of the two bottom rods and the lower ends of the two front foot tubes of the chair main body.

2. The adjustable folding chair as claimed in claim 1, wherein: the U-shaped pipe is sleeved on the upper section of the backrest rod, the top surface of the U-shaped pipe is hinged to the upper end of the first folding mechanism through a bolt, and the first folding mechanism can be hinged to the upper section of the backrest rod through the U-shaped pipe.

3. The adjustable folding chair as claimed in claim 2, wherein: the first folding mechanism comprises two crossed back cross pipes and a back support piece, the upper ends of the two back cross pipes are hinged with the upper section of the back rod, the middle parts of the two back cross pipes are hinged, the back support piece is used for connecting the upper sections of the two back cross pipes, and the two ends of the short rod are respectively hinged with the lower ends of the back cross pipes and the lower end of the back rod.

4. The adjustable folding chair as claimed in claim 3, wherein: the back support piece comprises a first support rod, a second support rod and a support clamping piece, the first support rod and the second support rod are respectively connected with the upper sections of the two back cross pipes, the support clamping piece is arranged between the first support rod and the second support rod, and the first support rod and the second support rod are controlled to be away from and close to each other through the support clamping piece.

5. The adjustable folding chair as claimed in claim 4, wherein: the support fastener is one end open-ended body, and the mounting hole has been seted up to the body side, and first bracing piece is inserted and is established in the opening, and the second bracing piece passes through the mounting hole and supports fastener swing joint, supports the fastener and still is equipped with the stopper for the home range of spacing second bracing piece.

6. The adjustable folding chair as claimed in claim 1, wherein: the tail end of the back support rod is connected with the rear end of the bottom rod through a connecting piece, the connecting piece main body is L-shaped, one side of the connecting piece is fixedly connected with the back support rod, and the other side of the connecting piece is movably connected with the bottom rod.

7. The adjustable folding chair as claimed in claim 1, wherein: two front foot tubes of the chair main body are hinged with the middle section of the bottom rod, two rear foot tubes of the chair main body are hinged with the tail end of the bottom rod through a rotating piece, the upper ends of the front foot tubes are hinged with the upper ends of the rear foot tubes and supported below two armrest pieces of the chair main body, and the rear ends of the armrest pieces are hinged with the lower end of the backrest rod.

8. The adjustable folding chair as claimed in claim 7, wherein: the handrail piece includes wooden handrail and fender position spare, keeps off the position spare and is located wooden handrail below, keeps off and is equipped with a plurality of constant head tanks on the position spare, and the articulated shaft joint of preceding, back foot pipe is in the constant head tank, through adjusting the angle of articulated shaft position in order to adjust back pole and sill bar in the constant head tank.

9. The adjustable folding chair as claimed in claim 1, wherein: the second folding mechanism comprises two front cross pipes which are crossed, the middle parts of the two front cross pipes are hinged, and two ends of each front cross pipe are connected with the bottom rod and the front leg pipe through hinge pieces respectively.

10. The adjustable folding chair as claimed in claim 9, wherein: the articulated piece is set up for the L type, and articulated piece one side is fixed on the front foot pipe, and articulated piece another side passes through the bolt and articulates with preceding crossing pipe.