CN215780993U

CN215780993U - Neck massager

Info

Publication number: CN215780993U
Application number: CN202120021085.7U
Authority: CN
Inventors: 刘杰; 王海峰
Original assignee: SKG Health Technologies Co Ltd.
Current assignee: SKG Health Technologies Co Ltd.
Priority date: 2021-01-04
Filing date: 2021-01-04
Publication date: 2022-02-11
Anticipated expiration: 2031-01-04

Abstract

The utility model discloses a neck massager, comprising: the inner side of the bracket main body is suitable for being attached to the neck of a human body and limiting a neck accommodating space, and the bracket main body is provided with a mounting hole; the side, far away from the massage head, of the connecting seat extends into the mounting hole, the connecting seat is provided with a flanging, and the connecting seat has elastic deformation capacity; the massage head is connected to one side of the connecting seat, which is far away from the bracket main body, and is suitable for being attached to the neck of a human body and providing a massage effect; the first fixing piece, the first fixing piece and the support main body clamp flanging to arrange the connecting seat in the support main body. Through set up the turn-ups on the connecting seat, and by first mounting and support main part centre gripping, fix the connecting seat in support main part department through the cooperation of first mounting and support main part promptly to the joint strength between connecting seat and the support main part can be promoted through the mode of centre gripping, avoids the user to tear the massage head out of support main part when dragging the massage head.

Description

Neck massager

Technical Field

The utility model relates to the technical field of neck massage instruments, in particular to a neck massage instrument.

Background

The neck massager is small and exquisite, can effectively replace manual massage, stretch tense muscles and bones of the whole body, relieve tension and oppression of a user, enable the whole body to be smooth, and can promote blood circulation of the whole body and accelerate metabolism, thereby achieving the effects of disease prevention, health care and body building. The principle of the device is that the electrode plate contacts with skin, and the massage effect is achieved through electric frequency pulse. By means of the low frequency therapy principle of pulse current, the pulse current with low frequency, small current and low voltage acts on nerve, muscle, etc. to promote local blood circulation, improve muscle state and relieve acute and chronic pain.

In the correlation technique, the connecting seat and the support main body can be integrated into one piece, so that the connecting seat and the support are inconvenient to be integrally formed, and the connecting strength of the connecting part of the connecting seat and the support main body is low after the connecting seat and the support main body are formed. Or the connecting seat is bonded at the position of the support body through glue, and the user can easily pull out the massage head due to the poor connecting strength of the connecting seat and the support body. .

SUMMERY OF THE UTILITY MODEL

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the utility model provides a neck massager, wherein the first fixing piece and the support main body are used for clamping and fixing the connecting seat, so that the connecting strength between the connecting seat and the support main body can be improved.

The neck massager according to the embodiment of the utility model comprises: the inner side of the bracket main body is suitable for being attached to the neck of a human body and limiting a neck accommodating space, and the bracket main body is provided with a mounting hole; the side, far away from the massage head, of the connecting seat extends into the mounting hole, the connecting seat is provided with a flanging, and the connecting seat has elastic deformation capacity; the massage head is connected to one side, far away from the support body, of the connecting seat and is suitable for being attached to the neck of a human body and providing a massage effect; the first fixing piece and the support main body clamp the flanging, so that the connecting seat is arranged on the support main body.

According to some embodiments of the utility model, the bracket main body is provided with an annular protrusion around the mounting hole, the connecting seat is further provided with a bent flange at the edge of the flange, the flange and the flange surround to form an annular groove, and at least a part of the annular protrusion is accommodated in the annular groove.

According to some embodiments of the utility model, the outer annular surface of the annular protrusion is configured with a guide surface arranged obliquely to guide the rib.

According to some embodiments of the utility model, a side of the first fixing piece facing the mounting hole is provided with a limiting boss, and a part of the connecting seat is located between the limiting boss and the annular protrusion to limit a side of the connecting seat away from the massage head.

According to some embodiments of the utility model, the stent body comprises: the first fixing piece is at least partially positioned between the outer shell and the inner shell and fixedly connected with the inner shell.

According to some embodiments of the utility model, the inner shell is provided with a first mounting post, and the first fixing member is provided with a through hole; the neck massager further comprises: the first fastening piece penetrates through the through hole to be connected with the first mounting column so as to press the part, extending into the bracket main body, of the connecting seat to the inner shell.

According to some embodiments of the utility model, the number of the first mounting posts is three, and a closed shape formed by sequentially connecting the centers of the three first mounting posts is a triangle, so as to play a fool-proof role.

According to some embodiments of the utility model, the end of the inner shell is provided with a second mounting post and the end of the outer shell is provided with a third mounting post; the neck massager further comprises: and the second mounting column is fixedly connected with the third mounting column through the second fastening piece.

According to some embodiments of the utility model, the neck massager further comprises: the massage head is provided with a connecting seat, the massage head is provided with a first fixing piece, one side of the massage head facing the connecting seat is provided with a mounting groove, one part of the connecting seat extends into the mounting groove, and the first fixing piece fixes one part of the connecting seat in the mounting groove.

According to some embodiments of the utility model, the massage head comprises: the top seat is arranged on one side, far away from the support main body, of the base, the base is provided with the mounting groove, and the top seat is provided with a fourth mounting column at a position corresponding to the mounting groove; the neck massager further comprises: and the second fixing piece is fixed on the fourth mounting column through a third fastening piece.

According to some embodiments of the utility model, the massage head further comprises: an electrode sheet, comprising: electrode main part with buckle the limit, buckle the limit connect in the edge of electrode main part, electrode main part pastes and locates the footstock deviates from a side surface of base, buckle the limit set up in the footstock with between the circumferential clearance of base.

According to some embodiments of the utility model, a limiting block is arranged on one side of the second fixing piece close to the massage head, a first limiting groove is arranged on a part of the connecting seat extending into the mounting groove, a second limiting groove is arranged on the massage head, and the limiting block is sequentially inserted into the first limiting groove and the second limiting groove.

According to some embodiments of the utility model, the connection socket comprises: first installation department, second installation department and connecting portion, connecting portion connect in first installation department with between the second installation department, the second installation department passes through the second mounting set up in massage head just first installation department passes through first mounting set up in support main part, connecting portion are in first installation department is horizontal cross sectional area diminishes progressively on the extending direction of second installation department.

According to the neck massager disclosed by the embodiment of the utility model, the flanging is arranged on the connecting seat, is arranged between the first fixing piece and the support main body and is clamped by the first fixing piece and the support main body, namely, the connecting seat is fixed at the support main body through the matching of the first fixing piece and the support main body, and the connection strength between the connecting seat and the support main body can be improved through a clamping mode, so that a user is prevented from pulling the massage head out of the support main body when pulling the massage head.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is an exploded view of a neck massager in accordance with an embodiment of the present invention;

FIG. 2 is a partial cross-sectional view of a neck massager of an embodiment of the present invention;

FIG. 3 is a partial schematic view of an exploded view of the neck massager;

FIG. 4 is a schematic structural view of the massage head, the connecting seat and the second fixing member;

fig. 5 is a schematic view of another angle structure of the massage head, the connecting seat and the second fixing member.

Reference numerals:

a neck massager S;

a holder main body 10; an inner shell 11; a mounting hole 111; an annular projection 112; a first mounting post 113; a second mounting post 114; a guide surface 115; a housing 12; a third mounting post 121;

a connecting seat 20; a first mounting portion 21; a flange 211; a rib 212; an annular groove 213; a second mounting portion 22; a first stopper groove 221; a connecting portion 23;

a massage head 30; a base 31; a mounting groove 311; a second retaining groove 312; a top seat 32; a fourth mounting post 321; an electrode sheet 33; an electrode main body 331; a bent edge 332;

a second fixing member 40; a stopper block 41; a first fixing member 50; a through hole 51; a limit boss 52; avoiding the groove 53.

Detailed Description

Embodiments of the present invention will be described in detail below, the embodiments described with reference to the drawings being illustrative, and the embodiments of the present invention will be described in detail below.

A neck massager S according to an embodiment of the present invention will be described below with reference to fig. 1 to 5.

As shown in fig. 1, the neck massager S includes: the massage device comprises a bracket main body 10, a connecting seat 20, a massage head 30 and a first fixing piece 50, wherein the inner side of the bracket main body 10 is suitable for being jointed with the skin of the neck of a human body and a neck accommodating space is limited. When the user wears the neck-holding bag, the neck of the user is held in the neck-holding space, so that the user can wear the neck-holding bag conveniently.

As shown in fig. 1, one end of the connecting seat 20 is connected with the support body 10, the connecting seat 20 has elastic deformation capability, because the connecting seat 20 has elastic deformation capability, when the massage head 30 is connected on one side of the connecting seat 20 far away from the support body 10, the massage head 30 can float relative to the support body 10, so that the massage head 30 can be attached to the skin of the neck of a human body in a floating manner, the adaptability of the neck massage instrument S is improved, so that the necks with different thicknesses can be accommodated in the neck accommodating space, and the massage head 30 can be attached to the neck of a user all the time, thereby avoiding the pricking feeling caused by the local contact of the massage head 30 and the neck of the user. The massage head 30 is adapted to engage the skin of the neck of a human body and provide a massage effect to the human body. Optionally, the connecting seat 20 is a plastic connecting seat, so that the massage head 30 can move along with the neck when the user rotates the neck, thereby improving the fitting performance.

As shown in fig. 2 and 3, the holder main body 10 is provided with a mounting hole 111, a side of the coupling holder 20 away from the massage head 30 is protruded into the mounting hole 111, and the coupling holder 20 is configured with a burring 211, and the burring 211 is disposed between the first fixing piece 50 and the holder main body 10 and is sandwiched by the first fixing piece 50 and the holder main body 10. Thus, the mounting hole 111 is formed in the bracket body 10, a part of the connecting base 20 can extend into the mounting hole 111, and the flange 211 is formed at one end of the connecting base 20, so that the flange 211 can be pressed around the mounting hole 111, and the flange 211 can be fixed around the mounting hole 111 by the fixed connection between the first fixing member 50 and the bracket body 10, thereby fixing the connecting base 20 on the bracket body 10.

Therefore, the flanging 211 is arranged on the connecting seat 20, the flanging 211 is arranged between the first fixing piece 50 and the bracket main body 10 and is clamped by the first fixing piece 50 and the bracket main body 10, namely, the connecting seat 20 is fixed at the bracket main body 10 through the matching of the first fixing piece 50 and the bracket main body 10, the connection strength between the connecting seat 20 and the bracket main body 10 can be improved through the clamping mode, and the user is prevented from tearing the massage head 30 out of the bracket main body 10 when the massage head 30 is pulled.

As shown in fig. 2 and 3, the bracket body 10 is provided with an annular protrusion 112 around the mounting hole 111, the connecting seat 20 is further provided with a bent rib 212 at an edge of the flange 211, the flange 211 and the rib 121 surround to form an annular groove 213, and at least a portion of the annular protrusion 112 is received in the annular groove 213. By providing the annular protrusion 112 on the periphery of the mounting hole 111, the structural strength of the periphery of the mounting hole 111 can be enhanced, so that the connecting seat 20 is prevented from deforming at the periphery of the mounting hole 111 when being connected with the periphery of the mounting hole 111 in a pressing manner. In addition, a rib 212 is further disposed on the connecting seat 20, the rib 212 and the flange 211 form an annular groove 213, and when the connecting seat 20 is fixedly connected with the bracket body 10, the annular protrusion 112 can be accommodated in the annular groove 213, so as to form a matching embedding structure, and the connecting strength between the connecting seat 20 and the bracket body 10 can be improved.

As shown in fig. 3, the outer circumferential surface of the annular protrusion 112 is configured with a guide surface 115 arranged obliquely, by which the rib 212 can be guided to facilitate the assembly of the coupling holder 20 with the annular protrusion 112.

As shown in fig. 3, the first fixing member 50 is provided with a stopper projection 52 at a side facing the mounting hole 111, and a portion of the coupling holder 20 is located between the stopper projection 52 and the annular projection 112 to stopper a side of the coupling holder 20 away from the massage head 30. That is, when the first fixing element 50 is connected to the connecting seat 20, the limiting boss 52 is in limiting fit with the connecting seat 20, so that the limiting boss 52 is matched with the annular protrusion 112 to clamp the connecting seat 20, thereby enhancing the connection strength between the connecting seat 20 and the bracket body 10, and preventing the user from pulling the connecting seat 20 and the massage head 30 when pulling the massage head 30.

As shown in fig. 1, the stent main body 10 includes: the outer shell 12 and the inner shell 11, the outer shell 12 is fixedly connected with the inner shell 11, the first fixing member 50 is positioned between the outer shell 12 and the inner shell 11, and the first fixing member 50 is fixedly connected with the inner shell 11. The first fixing member 50 is fixedly connected to the inner housing 11, so that the connecting base 20 is mounted on the inner housing 11, and thus the massage head 30 is mounted in the neck receiving space, so that the massage head 30 can be fitted and massaged with the neck of the user when the user wears the neck massage device.

As shown in fig. 3, the inner shell 11 is provided with a first mounting post 113, the first fixing member 50 is provided with a through hole 51, and the neck massager S further includes: and a first fastening member connected to the first mounting post 113 through the through hole 51. By passing the first fastening member through the through hole 51 and the first mounting post 113, the first fixing member 50 can be fixedly connected with the inner housing 11 because the flange 211 of the connecting socket 20 is disposed between the inner housing 11 and the first fixing member 50, so that the connecting socket 20 can be fixed on the inner housing 11, and the connection stability of the connecting socket 20 and the inner housing 11 can be improved.

As shown in fig. 3, the number of the first mounting posts 113 is three, and the closed shape formed by sequentially connecting the centers of the three first mounting posts 113 is a triangle, so as to perform the fool-proof function. Through setting up three first erection column 113 to the center of three first erection column 113 is connected in order and is formed triangle-shaped, can promote the joint strength of first fixing 50 with inner shell 11, avoids first fixing 50 to take place the dislocation. And set up three first erection column 113 and can play the effect of preventing slow-witted, avoid the position dress when the first mounting 50 is installed and turn over. The triangle may be an isosceles triangle. Alternatively, the first fastener may be a screw.

In addition, as shown in fig. 1 and 2, the end of the inner shell 11 is provided with a second mounting post 114, the end of the outer shell 12 is provided with a third mounting post 121, and the neck massager S further includes: the second fastener, the second mounting post 114, is fixedly connected to the third mounting post 121 by the second fastener. The inner housing 11 can be connected to the outer housing 12 by providing the second mounting post 114 on the inner housing 11 and the third mounting post 121 on the outer housing 12. In addition, as shown in fig. 1, an avoiding groove 53 is formed in a position of the first fixing member 50 corresponding to the second mounting column 114, and the avoiding groove 53 can avoid the second mounting column 114, so that the second mounting column 114 and the third mounting column 121 can be smoothly mounted. In addition, the third mounting post 121 and the avoiding groove 53 can cooperate to limit the rotation and the movement of the first fixing member 50, so as to prevent the massage head 30 from rotating when the user uses the massage head.

In addition, as shown in fig. 1 to 5, the neck massager S further includes: a second fixing member 40, the second fixing member 40 being fixedly connected with the massage head 30 such that the second fixing member 40 can fix the massage head 30 at the connecting seat 20. And, the first fixing member 50 is fixedly connected with the bracket body 10, and the first fixing member 50 fixes the connection holder 20 at the bracket body 10. Through the cooperation of the second fixing member 40 and the first fixing member 50, the connecting seat 20 and the massage head 30 can be fixed on the bracket main body 10, and the connection reliability of the connecting seat 20 between the bracket main body 10 and the massage head 30 can be ensured, i.e., when the user pulls the massage head 30 hard, the connecting seat 20 and the bracket main body 10 cannot be separated, or the massage head 30 and the connecting seat 20 are separated, so that the overall connection reliability of the neck massage instrument S can be improved.

As shown in fig. 4, a side of the massage head 30 facing the coupling holder 20 is provided with a mounting groove 311, a portion of the coupling holder 20 extends into the mounting groove 311, and the second fixing member 40 fixes a portion of the coupling holder 20 in the mounting groove 311. By providing the mounting groove 311 at a side of the massage head 30 facing the coupling seat 20, a portion of the coupling seat 20 may be inserted into the mounting groove 311, and the coupling seat 20 and the massage head 30 are fixedly coupled by the second fixing member 40, so that the massage head 30 may be fixed to the bracket body 10. In addition, since a portion of the coupling socket 20 may extend into the band mounting groove 311, the coupling gap between the coupling socket 20 and the massage head 30 may be hidden, so that the integrity of the neck massage apparatus S may be better.

As shown in fig. 4, the massage head 30 includes: base 31 and footstock 32, footstock 32 set up in the one side that the support main part 10 was kept away from to base 31, and base 31 is provided with mounting groove 311, and footstock 32 is provided with fourth erection column 321 in the position that corresponds mounting groove 311, and neck massager S still includes: and a third fastener, by which the second fixing member 40 is fixed to the fourth mounting post 321. The fourth mounting post 321 is arranged on the top seat 32, the second fixing member 40 can be connected with the massage head 30 by connecting the third fastener with the fourth mounting post 321 through the second fixing member 40, and the second fixing member 40 passes through the connecting seat 20, so that the connecting seat 20, the massage head 30 and the second fixing member 40 can be connected together. In addition, through set up fourth erection column 321 on footstock 32 for base 31 can be by connecting seat 20 and footstock 32 centre gripping, can realize the fixed to base 31 like this, need not set up adapting unit and links together base 31 and footstock 32, so can make things convenient for the assembly of neck massager S.

As shown in fig. 3 and 4, the massage head 30 further includes: the electrode sheet 33, the electrode sheet 33 includes: the electrode comprises an electrode main body 331 and a bent edge 332, wherein the bent edge 332 is connected to the edge of the electrode main body 331, the electrode main body 331 is attached to the surface of the top seat 32, which is away from the base 31, and the bent edge 332 is arranged between the circumferential gaps of the top seat 32 and the base 31. By dividing the electrode sheet 33 into the electrode main body 331 and the bending edge 332, the electrode main body 331 is attached to a side surface of the top seat 32 away from the base 31, and the electrode main body 331 is suitable for being attached to the neck skin of the user, so that the electrode sheet 33 can massage the neck skin of the user. In addition, the bending edge 332 can be inserted between the top seat 32 and the bottom seat 31, so that the electrode sheet 33 can be fixed at the massage head 30.

As shown in fig. 5, a limiting block 41 is disposed on one side of the second fixing member 40 close to the massage head 30, a first limiting groove 221 is disposed on a portion of the connecting seat 20 extending into the mounting groove 311, a second limiting groove 312 is disposed on the massage head 30, and the limiting block 41 is sequentially inserted into the first limiting groove 221 and the second limiting groove 312. The arrangement can prevent the massage head 30 from rotating by taking the second fixing piece 40 as a rotation center after being connected, thereby strengthening the connection strength between the second fixing piece 40 and the connecting seat 20 and the massage head 30.

As shown in fig. 3, the connection socket 20 includes: the massage head comprises a first mounting portion 21, a second mounting portion 22 and a connecting portion 23, wherein the connecting portion 23 is connected between the first mounting portion 21 and the second mounting portion 22, the second mounting portion 22 is arranged on the massage head 30 through a second fixing piece 40, the first mounting portion 21 is arranged on the bracket main body 10 through a first fixing piece 50, and the cross section area of the connecting portion 23 decreases in the extending direction of the first mounting portion 21 to the second mounting portion 22. Through making connecting portion 23 horizontal cross-sectional area in the extending direction of first installation department 21 to second installation department 22 decrement, that is to say, the cross-sectional area of connecting seat 20 in the one side that is close to massage head 30 is less than the cross-sectional area of connecting seat 20 near support main part 10 one side, so set up can make connecting seat 20 conveniently take place to warp in the one side that is close to massage head 30, can make things convenient for massage head 30 to float like this to make massage head 30 more laminate user's neck skin.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the utility model and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the utility model.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the utility model have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the utility model, the scope of which is defined by the claims and their equivalents.

Claims

1. A neck massager, comprising:

the inner side of the bracket main body is suitable for being attached to the neck of a human body and limiting a neck accommodating space, and the bracket main body is provided with a mounting hole;

the side, far away from the massage head, of the connecting seat extends into the mounting hole, the connecting seat is provided with a flanging, and the connecting seat has elastic deformation capacity;

the massage head is connected to one side, far away from the support body, of the connecting seat and is suitable for being attached to the neck of a human body and providing a massage effect;

the first fixing piece and the support main body clamp the flanging, so that the connecting seat is arranged on the support main body.

2. The neck massager of claim 1 wherein the bracket body is provided with an annular protrusion around the mounting hole, the connecting base is further provided with a bent rib at an edge of the flange, the flange and the rib surround to form an annular groove, and at least a portion of the annular protrusion is received in the annular groove.

3. The neck massager of claim 2 wherein the outer circumferential surface of the annular protrusion is configured with a guide surface arranged obliquely to guide the rib.

4. The neck massager of claim 2 wherein the first fixing member is provided with a limiting boss at a side facing the mounting hole, and a portion of the connecting seat is located between the limiting boss and the annular protrusion to limit a side of the connecting seat away from the massage head.

5. The neck massager of claim 1 wherein the support body comprises: the first fixing piece is at least partially positioned between the outer shell and the inner shell and fixedly connected with the inner shell.

6. The neck massager of claim 5 wherein the inner shell is provided with a first mounting post and the first securing member is provided with a through hole;

the neck massager further comprises: the first fastening piece penetrates through the through hole to be connected with the first mounting column so as to press the part, extending into the bracket main body, of the connecting seat to the inner shell.

7. The neck massager of claim 6 wherein the number of the first mounting posts is three, and the closed shape formed by connecting the centers of the three first mounting posts in sequence is triangular, so as to prevent fool.

8. The neck massager of claim 5 wherein the end of the inner shell is provided with a second mounting post and the end of the outer shell is provided with a third mounting post;

the neck massager further comprises: and the second mounting column is fixedly connected with the third mounting column through the second fastening piece.

9. The neck massager of claim 1 further comprising: the massage head is provided with a connecting seat, the massage head is provided with a first fixing piece, one side of the massage head facing the connecting seat is provided with a mounting groove, one part of the connecting seat extends into the mounting groove, and the first fixing piece fixes one part of the connecting seat in the mounting groove.

10. The neck massager of claim 9 wherein the massage head comprises: the top seat is arranged on one side, far away from the support main body, of the base, the base is provided with the mounting groove, and the top seat is provided with a fourth mounting column at a position corresponding to the mounting groove;

the neck massager further comprises: and the second fixing piece is fixed on the fourth mounting column through a third fastening piece.

11. The neck massager of claim 10 wherein the massage head further comprises: an electrode sheet, comprising: electrode main part with buckle the limit, buckle the limit connect in the edge of electrode main part, electrode main part pastes and locates the footstock deviates from a side surface of base, buckle the limit set up in the footstock with between the circumferential clearance of base.

12. The neck massager of claim 9 wherein the second fixing member is provided with a stopper at a side thereof adjacent to the massage head, a first stopper groove is provided at a portion of the connecting seat extending into the mounting groove, and a second stopper groove is provided at the massage head, and the stopper is sequentially inserted into the first stopper groove and the second stopper groove.

13. The neck massager of claim 9 wherein the attachment base comprises: first installation department, second installation department and connecting portion, connecting portion connect in first installation department with between the second installation department, the second installation department passes through the second mounting set up in massage head just first installation department passes through first mounting set up in support main part, connecting portion are in first installation department is horizontal cross sectional area diminishes progressively on the extending direction of second installation department.