CN111528861A

Movatterモバイル変換

Info

Publication number: CN111528861A
Application number: CN202010396234.8A
Authority: CN
Inventors: 胡超宇
Original assignee: Pu'ang Hangzhou Medical Technology Co ltd
Current assignee: Pu'ang Hangzhou Medical Technology Co ltd
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2020-08-14

Abstract

The invention discloses a launching auxiliary motion central shaft offset launching rod and a safety hemostix, wherein the launching auxiliary motion central shaft offset launching rod at least comprises a launching rod base part, a needle seat and a launching auxiliary rod, the needle seat is arranged on the front side of the launching rod base part, and the needle seat is provided with a main motion central shaft; the launching auxiliary rod is provided with a launching auxiliary motion central shaft which is eccentrically arranged relative to the main motion central shaft. In the invention, the driving force direction borne by the main motion direction of the blood taking needle is staggered with the driving force direction generated by the first spring, so that the direct action of the driving force can be avoided, the impact feeling on a blood collector is reduced, the pain feeling is reduced, in addition, the offset design enlarges the internal space at one side of the shell where the non-emission auxiliary rod is positioned, more abundant space can be provided for arranging other mechanisms such as a push rod mechanism and the like, the utilization rate of the space is better, and the arrangement of the internal space is more reasonable.

Description

Emission rod with offset emission pair motion central shaft and safety hemostix

Technical Field

The invention relates to the technical field of medical hemostix, in particular to an emission rod with an offset emission pair motion central axis and a safety hemostix.

Background

In a medical blood collection device, a blood collector is used in cooperation with a blood collection needle for collecting a small amount of blood from the skin of a human body. Wherein, the blood taking needle is disposable, and the hemostix can be repeatedly used for a plurality of times.

Among them, a lancet device generally has a firing rod, one end of which is used for mounting a disposable lancet, and the other end of which is used for mounting a spring to provide an ejection driving force and an elastic restoring force. The movement central axis of one end of the launching rod, which is provided with the blood taking needle, is set as a main movement central axis, and the movement central axis of one end of the launching rod, which is provided with the spring, is set as a launching auxiliary movement central axis.

Generally, the main movement center axis and the sub-movement center axis of the above-described firing rod are coaxially disposed. For example, the invention patent publication No. CN108078571A discloses a safety blood collector in which a movement center axis (main movement center axis) of a holder 82 for mounting a disposable blood collection needle is coaxial with a movement center axis (emission sub movement center axis) of a cross rib 88 for mounting first to third springs.

For another example, chinese utility model patent publication No. CN209332069U discloses a blood sampling pen with biased guiding and secondary puncture prevention, wherein the movement center axis (main movement center axis) of theneedle holder 14 where the head of the injection rod 3 is located is coaxial with the movement center axis (auxiliary movement center axis) of the positions where the launching spring 5 and the return spring 9 are located.

In the prior art, the coaxial arrangement of the main motion central axis and the launching auxiliary motion central axis of the launching rod has the defects that the accumulated error in the motion direction is large, the vibration is large in the using process, the puncture depth is not accurate, and the pain of a user is large; in addition, the transmitting elements occupy more space and cross each other, which may adversely affect each other.

Disclosure of Invention

The invention aims to solve the technical problem of solving the technical defect caused by the coaxial arrangement of the main motion central shaft and the auxiliary motion central shaft of the launching rod of the hemostix in the prior art.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: a shooting secondary offset motion center axis shooting bar, comprising at least:

a firing rod base;

a needle hub disposed at a front side of the firing rod base, the needle hub having a primary motion center axis; and

the launching auxiliary rod is arranged on one side, far away from the needle base, of the launching rod base, and is provided with a launching auxiliary motion central shaft which is eccentrically arranged relative to the main motion central shaft.

A safety blood collector at least comprises:

a firing rod that is the offset-launch secondary motion center shaft firing rod of claim 1;

the transmitting rod is arranged in the shell, the shell is coaxial with a main movement central shaft of the transmitting rod, and the transmitting rod has at least three working states in the axial direction in the shell, namely a balance state, an energy storage state and a needling state;

a cap mounted to a front end of the housing;

a pulling mechanism mounted at a rear end of the housing and configured to move the firing rod from a self-balancing state to an energy-storing state;

the trigger mechanism is used for releasing the energy storage state of the emission rod;

the first spring is sleeved on the launching auxiliary rod and is configured to store energy in an energy storage state, and the launching rod is driven by the first spring to move to a needling state after the energy storage state of the launching rod is released;

a second spring configured to move the firing rod from the needle-piercing state to the equilibrium state.

In a preferred embodiment, the housing includes an outer housing and an inner housing, the front end of the inner housing is inserted into the outer housing from the rear end of the outer housing, and a first locking mechanism is disposed between the inner housing and the outer housing.

In a preferred embodiment, the first locking mechanism comprises at least:

the at least two first elastic arms extend from the front end of the inner shell along the axial direction;

the first convex is arranged on the first elastic arm and protrudes out of the outer wall of the inner shell from the outer surface of the first elastic arm;

the first clamping groove is formed in the inner wall of the outer shell and configured to correspond to the first convex in a one-to-one mode, and the inner shell is fixed in the outer shell through the matching of the first clamping groove and the first convex.

In a preferred embodiment, the inner housing comprises at least:

a flange base;

an inner casing front base disposed on a side of the flange base facing the outer casing and configured to extend into the outer casing, the inner casing front base being configured with a first inner cavity,

the inner shell rear base body is arranged on one side, away from the inner shell front base body, of the flange base portion, and is provided with a second inner cavity;

the cavity space bar, the cavity space bar sets up between the cavity in first interior cavity and the second, be provided with the intercommunication on the cavity space bar the first perforation of cavity in first interior cavity and the second.

The free end of the launching auxiliary rod is provided with a spring clamping end, the launching auxiliary rod is configured to be the clamping end of the launching auxiliary rod which penetrates through a first perforation from a first inner cavity to enter a second inner cavity, the first spring is sleeved on the launching auxiliary rod and is configured between a cavity spacing plate and a launching rod base, and the second spring is sleeved on the launching auxiliary rod and is configured between the spring clamping end and the cavity spacing plate.

In a preferred embodiment, the pulling mechanism comprises at least:

the pull plug is arranged in the second inner cavity and is configured to only axially move in the second inner cavity, a spring cavity is arranged in the pull plug, a spring cavity bottom plate is arranged in the spring cavity, a second through hole for accommodating the spring clamping end of the launching auxiliary rod to penetrate is formed in the spring cavity bottom plate, and the second spring is configured in the spring cavity;

the pull cylinder is axially and movably connected with the second inner shell and is configured to be provided with a second locking mechanism between the pull cylinder and the pull plug.

In a preferred embodiment, the trigger mechanism comprises at least:

the elastic trigger arm is arranged on the launching rod and configured to extend from the base of the launching rod to one side of the needle seat, and a trigger stop block protruding out of the outer surface of the launching rod is arranged at the end part of the free end of the elastic trigger arm;

the inner blocking part is arranged on the inner side of the shell and is configured to be matched with the stop block to limit the launching rod in an energy storage state;

a trigger button protrudingly disposed on an outer wall of the housing and configured to apply pressure on the stopper to separate the stopper from the inner barrier.

In a preferred embodiment, the firing rod is provided with a marking portion, and the housing or the trigger button is provided with a transparent portion and configured to recognize the marking portion through the transparent portion.

The preferred embodiment further comprises a push rod mechanism, the push rod mechanism at least comprises a push button, a shell guide rod and a push rod, the shell is provided with a guide groove matched with the shell guide rod, and the needle seat is provided with a push rod groove matched with the push rod.

Compared with the prior art, the emission rod with the offset emission pair motion central axis and the safety hemostix with the emission rod with the offset emission pair motion central axis have the following beneficial effects:

(1) the launching auxiliary motion central shaft and the main motion central shaft of the launching rod are not arranged coaxially, but are arranged eccentrically, so that the driving force direction borne by the main motion direction of the blood taking needle and the driving force direction generated by the first spring are in a staggered state, the direct action of the driving force can be avoided, the impact on a blood collector is reduced, and the pain is reduced.

(2) The offset design of the launching auxiliary motion center of the launching rod enlarges the inner space on one side of the shell where the non-launching auxiliary rod is positioned, so that more abundant space can be provided for arranging other mechanisms such as a push rod mechanism, the utilization rate of the space is better, and the arrangement of the inner space is more reasonable.

(3) In the prior art, both the pull plug and the pull cylinder can rotate, and actually, in the application of a product, the rotation motion is redundant motion, so that not only is no positive contribution made, but also the motion precision is reduced.

(4) In the prior art, an inner shell is usually connected to the front side outside an outer shell and locked in a hard extrusion mode of a plastic part, and the fixing mode has the defects that the installation is complicated, the deformation of the shell cannot be accurately controlled, the moving center of a shooting rod is eccentric due to the deformation of the shell, and the precision is reduced; and in this application, interior casing inserts from the shell body, and realizes fixing between the two through first latched device, so set up the back, simple to operate, only need interior casing from the rear side insert the shell body can, first latched device triggers to realize the two fixed, can not cause shell structure's deformation simultaneously, the motion accuracy is higher.

Drawings

FIG. 1 is a schematic front view of a transmission rod with offset transmission pair motion centers according to the present embodiment;

FIG. 2 is a schematic perspective view of the offset center of motion emitter rod of the emitter pair of FIG. 1;

FIG. 3 is a schematic view of another angular perspective of the offset center of motion firing rod of the firing pair of FIG. 2;

FIG. 4 is a schematic structural diagram of the safety blood collector of the present embodiment;

FIG. 5 is another angle of the safety blood collector shown in FIG. 4

FIG. 6 is a schematic diagram of the safety blood collector in an exploded state according to the present embodiment;

FIG. 7 is a schematic structural diagram of the outer housing in the present embodiment;

FIG. 8 is a schematic view of the outer housing shown in FIG. 7 at another angle;

FIG. 9 is a schematic structural view of the inner housing of the present embodiment;

FIG. 10 is a rear side view of the inner housing of FIG. 9;

FIG. 11 is a schematic view of the connection between the stopper and the pull cup in this embodiment;

FIG. 12 is a schematic structural view of the stopper in this embodiment;

FIG. 13 is a schematic view of another angle structure of the plug of the present embodiment;

fig. 14 is a schematic view of the internal structure of the pulling barrel in the present embodiment;

fig. 15 is a schematic structural view of the safety hemostix of the present embodiment after the outer casing is hidden;

FIG. 16 is a schematic structural diagram of the push rod mechanism in the present embodiment;

fig. 17 is a schematic sectional view of the safety blood collector of the present embodiment in an energy storage state;

FIG. 18 is a cross-sectional view of the safety hemostix in the energy storage state in accordance with the present embodiment;

FIG. 19 is a schematic sectional view of the safety blood collector of the present embodiment in a balanced state;

FIG. 20 is a schematic sectional view of the safety blood collector of this embodiment in a needle-pricked state;

fig. 21 is a schematic partial sectional view showing the structure of the safety hemostix during pushing the needle.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, integrally connected, or detachably connected; may be communication within two elements; they may be directly connected or indirectly connected through an intermediate, and those skilled in the art will understand the specific meaning of the above terms in the present invention in specific situations.

A shooting secondary motion center axis offsettype shooting rod 10 of the present embodiment, as shown in fig. 1 to 3, is provided with a shootingrod base 11, aneedle holder 12, and a shootingsecondary rod 13. Wherein, theneedle seat 12 is arranged at the front side of the base of the launching rod (the end close to the blood taking needle is limited as the front side, and the reverse side).

In this embodiment, thehub 12 is used for mounting thedisposable lancet 200, and it should be noted that the structure of the hub is a common structure, as shown in fig. 3, the hub has a mountingcavity 121 for mounting thedisposable lancet 200, as shown in fig. 2, the mountingcavity 121 has acavity bottom 122, and since the safety lancet is a reusable component and thedisposable lancet 200 is a disposable component, in order to facilitate replacement of thedisposable lancet 200, thehub 12 is provided with afirst plunger groove 123 penetrating through an outer wall of the mountingcavity 121 and thecavity bottom 122. Corresponding to the firstpush rod groove 123, the firingrod base 11 has a secondpush rod groove 112 corresponding to the firstpush rod groove 123. In this embodiment, a thirdpush rod groove 111 is further included, which is communicated with the secondpush rod groove 112, and the secondpush rod groove 112 and the thirdpush rod groove 111 form a push rod groove adapted to thepush rod 44. Correspondingly, thecavity bottom 122 has an opening corresponding to the thirdpush rod groove 111.

In this embodiment, a preferred arrangement is to provide anengagement 14 between thehub 12 and the firingrod base 11, the purpose of theengagement 14 being to provide space for theresilient trigger arm 15.

In this embodiment, theelastic trigger arm 15 is configured to extend from the base of the firing rod to one side of the needle holder, the free end of theelastic trigger arm 15 is provided with atrigger stopper 16 protruding from the outer surface of the firing rod, and one side of thetrigger stopper 16 facing theneedle holder 12 has anabutment surface 161.

In this embodiment, a launchingauxiliary rod 13 is arranged on one side of the launchingrod base 11 far away from theneedle base 12, and a spring clamping end is arranged at the free end of the launchingauxiliary rod 13. In this embodiment, the spring clamping end includes a pair of clampingarms 131 arranged oppositely, agap 132 is provided between the clampingarms 131, a clamping joint 133 protruding outwards is provided at the end of the free end of theclamping arm 131, a clampinggroove 134 is provided at the inner side of the clamping joint 133, and the clampinggroove 134 is used for accommodating the clamping spring.

As the greatest improvement of the present embodiment, wherein the launchingsub-rod 13 has a launching sub-movement central axis B, and thehub 12 has a main movement central axis a, which is the movement central axis of thedisposable lancet 200. In the present embodiment, the emission pair movement center axis B is offset from the main movement center axis a instead of being concentrically arranged.

In the prior art, the central axis B of the launching pair motion and the central axis a of the main motion are generally coaxially arranged. The coaxial arrangement has certain drawbacks. After the eccentric setting of this embodiment is adopted, the accumulative total error on the motion center axle of disposable blood taking needle is littleer, and the acupuncture accuracy is higher, and the sense of pain is littleer.

In this embodiment, the launchingauxiliary rod 13 is sleeved with afirst spring 80 as a main drive and asecond spring 81 as a restoring action, and the specific installation manner will be described in detail below.

The safety blood collector of the present embodiment, which includes the above-mentioned emission rod with offset central axis of emission pair motion, as shown in fig. 4-6, includes a housing, acap 50, a pulling mechanism and a trigger mechanism. Thecap 50 is mounted at the front end of the housing, and it should be noted that the cap is a conventional structure, and is not described in detail herein.

In this embodiment, the structure of the housing is as shown in fig. 6 to 10, and includes anouter housing 20 and aninner housing 30, where theinner housing 30 includes aflange base 33, an innerhousing front base 31, and an inner housingrear base 32 as shown in fig. 9 and 10. Wherein the innerhousing front base 31 is provided on a side of theflange base 33 facing theouter housing 20 and configured such that the rear end of theouter housing 20 is inserted into the outer housing.

The innerhousing front base 31 of this embodiment is configured with a firstinner cavity 311, and the firstinner cavity 311 is used for accommodating the shootingrod 10. The inner casingrear base 32 of the present embodiment is disposed on the side of theflange base 33 away from the innercasing front base 31, and the inner casingrear base 32 is provided with a secondinner cavity 321. Acavity partition plate 34 is arranged between the first inner cavity and the second inner cavity, and afirst perforation 341 communicating the first inner cavity with the second inner cavity is arranged on thecavity partition plate 34.

In this embodiment, a first locking mechanism is disposed between theinner housing 30 and theouter housing 20, and the first locking mechanism includes two firstelastic arms 38 disposed oppositely, and the firstelastic arms 38 extend axially from the front end of the inner housing. Wherein, the free end of the first elastic arm is provided with afirst protrusion 381 protruding from the outer surface of the first elastic arm. Correspondingly, as shown in fig. 8, the inner wall of the outer shell is also provided with first lockinggrooves 25 corresponding to the first protrusions one by one. The inner shell is fixed in the outer shell through the matching of the first clamping groove and the first convex.

Preferably, a first guiding mechanism is further disposed between the inner housing and the outer housing, and the first guiding mechanism includes afirst guiding groove 24 disposed on the inner wall of the outer housing, and a first guidingrib 35 disposed on the outer wall of the inner housing corresponding to the first guidinggroove 24. The first guide mechanism is used for ensuring that the inner shell and the outer shell are accurately connected together through the first locking mechanism.

The shell structure of this embodiment, simple to operate only need interior casing from the rear side insert the shell body can, first latch mechanism triggers to realize the two fixed, can not cause shell structure's deformation simultaneously, and the motion precision is higher.

In this embodiment, the installation manner of the launching rod is that the spring clamping end of the launching auxiliary rod passes through the first through hole from the first inner cavity and enters the second inner cavity, the first spring is sleeved on the launching auxiliary rod and is arranged between the cavity spacing plate and the launching rod base, and the second spring is sleeved on the launching auxiliary rod and is arranged between the spring clamping end and the cavity spacing plate.

Preferably, in the present embodiment, a second guiding mechanism is disposed between the firing rod and the inner housing, and the second guiding mechanism includes asecond guiding rib 17 disposed on the firing rod and asecond guiding groove 39 disposed on the inner wall of the inner housing matching with the second guiding rib. Preferably, in the present embodiment, thesecond guide groove 39 is disposed inside the firstelastic arm 38. The mechanism of the second guide mechanism is used for improving the axial movement precision of the launching rod and the puncture precision of the blood taking needle.

The pulling mechanism in this embodiment, as shown in fig. 10-14, includes apull plug 70 and apull cup 60. Wherein thestopper 70 is disposed within the second inner cavity and is configured to be axially movable only within the second inner cavity. Specifically, in a preferred mode of this embodiment, the secondinner cavity 321 has a limitingrib 322 disposed opposite to the second inner cavity, one side of the first throughhole 341 forms aplug cavity 323, theplug 70 has a limitingplane 76 in adaptive contact with the limitingrib 322, and based on the interaction between the limitingrib 322 and the limitingplane 76, the plug can only move axially but not rotate in the second inner cavity. The advantage of such an arrangement is that the redundant, inefficient degrees of freedom (rotational movement) are eliminated, increasing the accuracy of the system.

Theplunger 70 of this embodiment is provided with aspring chamber 71 as shown in fig. 13, thespring chamber 71 being provided with a springchamber bottom plate 72, the springchamber bottom plate 72 being provided with a second throughhole 73 through which a spring snap end of the fire sub-rod is received, the second spring being disposed in the spring chamber. Preferably, in order to facilitate the passing of the spring clamping end, the second throughhole 73 includes a main throughhole 731 and auxiliary throughholes 732 disposed at both sides. Correspondingly, the first through hole has the same shape as the second through hole.

In this embodiment, a second locking mechanism is disposed between the pull cylinder and the pull plug, the second locking mechanism includes a pair of throughslots 74 disposed on the side walls of thepull plug 70, and aprotrusion 75 is disposed in the middle of the throughslots 74. Correspondingly, a pair ofelastic arms 62 arranged with the throughgrooves 74 are arranged in theinner cavity 61 of thepull cylinder 60, and the free end parts of the elastic arms are provided withconvex parts 63 protruding inwards. In the installation process, the free end of the elastic arm is inserted from the rear end of the through groove of the pull plug until the elastic arm deforms to cause the convex part to cross the protrusion, so that in the process of pulling the pull cylinder, the pull cylinder can be pulled to move backwards by the resistance of the protrusion to the convex part.

Further, a third guiding mechanism is arranged between the inner wall of the slide and the outer wall of the inner shellrear base body 32, and the third guiding mechanism comprises athird guiding rib 324 arranged on the outer wall of the inner shell rear base body and athird guiding groove 64 matched with the third guiding rib and located on the inner wall of the slide.

The trigger mechanism of this embodiment mainly includes aresilient trigger arm 15, an internal barrier and atrigger button 90. Specifically, as shown in fig. 9, awindow 36 is formed on the inner housing, aninner blocking portion 37 is disposed on the front side of thewindow 36, and the inner blocking portion cooperates with thefirst protrusion 381 to limit the firing rod in the energy storage state. As shown in fig. 7 and 8, the outer housing is provided with aninstallation opening 23 for installing the trigger button.

Preferably, in the present embodiment, the emitting rod is provided with amark portion 92, and the housing or the trigger button is provided with a transparent portion and configured to recognize the mark portion through the transparent portion. In this embodiment, the trigger button is provided with atransparent portion 91. Through transparent portion and sign portion, the operating condition of discernment safe formula hemostix that can be accurate.

The safety blood collector of the present embodiment further includes a pushingrod mechanism 40. As shown in fig. 15 and 16, the push rod mechanism at least comprises apush button 41, ahousing guide rod 42 and apush rod 44, wherein apartial gap 45 is formed between thepush rod 44 and thehousing guide rod 42 to avoid the internal structure of the housing. In cooperation therewith, as shown in fig. 7, the outer housing is provided with a housing guide throughslot 22 adapted to the housing guide rod. Aguide sinking groove 21 is formed on the outer side of the housing guide throughgroove 22, and anauxiliary guide rod 43 is provided on thepush rod mechanism 40 corresponding to theguide sinking groove 21.

The safety lancet of this embodiment has three operating states of the firing rod in the housing, as shown in fig. 17 and 18, which are energy accumulating states in which the first spring is compressed to store elastic potential energy. When the trigger button is pressed, the energy storage state of the launching rod is released, the launching rod launches under the action of the first spring to a acupuncture state shown in fig. 20, in which the needle head of the disposable blood taking needle extends out of the cap to complete blood taking, and in which the second spring is compressed to store elastic potential energy. Immediately thereafter, the firing rod returns to its natural state shown in fig. 19 under the action of the second spring. In this state, the disposable blood collection needle can be replaced. As shown in figure 21, the cap is removed, the push rod mechanism is pushed, the disposable blood taking needle in the needle stand can be pushed out, then a new disposable blood taking needle is replaced, and the cap is installed. And then the pull cylinder is pulled, and the transmitting rod in a balanced state is pulled to an energy storage state through the pull plug and the second spring in sequence so as to carry out the next blood sampling action.

In conclusion, the above description is only for the preferred embodiment of the present invention and should not be construed as limiting the present invention, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An offset central axis of motion firing rod for a firing pair, comprising at least:

a firing rod base;

2. A safety blood collector is characterized by at least comprising:

a cap mounted to a front end of the housing;

3. The safety hemostix according to claim 2, wherein the housing comprises an outer housing and an inner housing, wherein the front end of the inner housing is inserted into the outer housing from the rear end of the outer housing, and a first locking mechanism is disposed between the inner housing and the outer housing.

4. The safety hemostix according to claim 3, wherein the first locking mechanism comprises at least:

5. The safety hemostix of claim 3, wherein the inner housing comprises at least:

a flange base;

6. The safety hemostix according to claim 5, wherein the free end of the secondary rod is provided with a spring engaging end, the secondary rod is configured such that the engaging end of the secondary rod passes through the first through hole from the first inner cavity to the second inner cavity, the first spring is sleeved on the secondary rod and is disposed between the cavity spacer and the base of the secondary rod, and the second spring is sleeved on the secondary rod and is disposed between the spring engaging end and the cavity spacer.

7. The safety hemostix according to claim 6, wherein the pulling mechanism comprises at least:

8. The safety lancing device according to claim 7, wherein the trigger mechanism comprises at least:

9. The safety hemostix according to claim 8, wherein the emitting rod is provided with a mark portion, and the housing or the trigger button is provided with a transparent portion and configured to recognize the mark portion through the transparent portion.

10. A safety hemostix according to any one of claims 1-9 further comprising a pusher mechanism including at least a push button, a housing guide bar and a pusher bar, wherein said housing is provided with a guide groove adapted to said housing guide bar, and said hub is provided with a pusher groove adapted to said pusher bar.