Patent Application
20180100526
The present disclosure relates to a method for assembling members, and particularly to an assembly provided with at least one polymer member and a method for assembling thereof.
Shape memory polymer (SMP) is a new kind of functional polymer material. According to various induced external stimulus, there are various types of shape memory polymers, such as thermo-induced SMPs, light-induced SMPs, and acid/base-induced SMPs. Currently, thermo-induced SMP is the most common polymer, which is also named as heat shrink material. This property of polymer material is called shape memory effect. Shape memory polymers may have various types, such as cross-linked polyolefin, polyurethane, polyester, where commonly used polyolefin polymers include polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polylactic acid (PLA) and ethylene/vinyl acetate (vinyl acetate) acetate copolymer (EVA).
Taking PTFE as an example, it is often used as a non-stick coating or easy-for-cleaning material, which has no reaction with respect to acid, alkali, or various organic solvents, and is almost insoluble in all solvents. Furthermore, combined with its high melting temperature and one of the lowest coefficients of friction of any solid, PTFE is also frequently employed as not only lubricant, but also ideal coating for inner walls of water pipes on purpose of easy-cleaning.
Members made of polymer, especially PTFE, are usually need to be assembled with other members so as to form an assembly having specific functions, however, generally PTFE members cannot be engaged with other members stably and reliably. For example, an ultrasonic instrument comprises a clamp arm (also refers to jaw member) that may be actuated to open or close by a mechanism, to thereby clamp tissue or vessels. In order to prevent a waveguide of the ultrasonic instrument from contacting directly with a metal clamp arm, it is preferred to provide the clamp arm with a PTFE tissue pad thereon.
The clamp arm of the above mentioned ultrasonic instrument further comprises a T-shaped or wedge-shaped slot for receiving at least one portion of the tissue pad, where engagement therebetween is fixed by adhesive or glue.
However, because of the properties of PTFE material, it is difficult to find an adhesive that can be attached with the tissue pad made of PTFE reliably, which makes the engagement between the tissue pad and the clamp arm unreliable. Therefore, it often happens during operation that the tissue pad slips or falls out of the slot of the clamp arm, increasing surgery risks.
Therefore, it is provided in the present disclosure a method for assembling members, at least one of which is a polymer member, so as to providing reliable engagement therebetween.
The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limiting, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention.
It is provided in one of the embodiments of the present disclosure an assembly and an assembling method thereof, as shown in
In addition or alternatively, the connecting portion 21 of the polymer member 2 may be in interference-fit engagement with the connecting member 1, therefore, an adhesive or glue would no longer be necessary for ensuring engagement therebetween, so as to enhance reliability of the engagement and facilitate assembling. It is preferred that the polymer member is made of fluorine polymer; more specifically, the polymer member is made of polytetrafluoroethylene (PTFE). In an alternative embodiment, the polymer member is made of polyethylene; more specifically, the polymer member is made of ultra-high molecular weight polyethylene (UHMWPE).
It should be noted that polymers mentioned in any one of the embodiments of the present disclosure comprise engineering polymers having shape memory effect, including but not limited to polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polylactic acid (PLA) and ethylene-vinyl acetate (vinyl acetate) acetate copolymer (EVA), etc. Therefore, assemblies, which are made of engineering polymers having shape memory effect and assembled according to the method described herein, all fall in the scope of the present disclosure.
In an alternative embodiment, as shown in
In an alternative embodiment, the connecting member 1 comprises at least an aperture that is configured to be engaged with the connecting portion 21 of the polymer member 2 being inserted thereinto. Preferably, the polymer member 2 is in interference-fit engagement with the connecting member 1. Referring to
step S101, deforming at least one portion of the polymer member; referring to
step S102 is putting the deformed connecting portion 21 of the polymer member 2 into the connecting member 1, for example, inserting the connecting portion 21 of the polymer member 2 into the slot 11 of the connecting member 1, as shown in
furthermore, step S103 is heating the deformed connecting portion 21 of the polymer member 2, allowing the deformed connecting portion 21 to recover so as to be further engaged with the connecting member 1. It is preferred that the connecting portion 21 of the polymer member 2 is in interference-fit engagement with the connecting member 1. Alternatively, the connecting portion 21 of the polymer member 2 may also be in interference-fit engagement with the slot 11 arranged in the connecting member 1, which is to form a circular sealing portion around the side wall of the slot 11 of the connecting member 1, as shown in
Deformation against the polymer member 2 may be performed in two manners during assembling thereof according to the above mentioned method, which are:
(1) compressing the polymer member 2, specifically, compressing the connecting portion 21 of the polymer member 2 through a tooling for narrowing dimensions thereof; or (2) stretching the polymer member 2, specifically, stretching the connecting portion 21 of the polymer member 2 through a tooling for narrowing dimensions thereof.
The connecting portion 21 of the polymer member 2 may be narrowed through the processes described above, allowing itself to be smoothly inserted into the slot 11 or the aperture of the connecting member 1. Further, after being heated at step S103, the connecting portion 21 of the polymer member 2 may be recovered towards its original shape, so as to be in interference-fit engagement with the slot 11 or aperture of the connecting member, based on which, adhesive is no longer necessary for improving reliabilities of engagement therebetween.
More specifically, in the step S103, heating the connecting portion 21 of the polymer member 2 for shape recovery may further comprise a step of: heating the deformed connecting portion 21 of the polymer member 2 to about 80° C.-400° C., yet below the melting point thereof, allowing the deformed connecting portion 21 to recover.
In one embodiment, the polymer member 2 is made of fluorine polymer; for example, the polymer member 2 is made of PTFE. The step S103 of heating the deformed connecting portion 21 thereby allows it to recover, may further comprise a step of:
heating the deformed connecting portion 21 of the PTFE member 2 to about 140° C.-350° C., so as to recover the deformed connecting portion 21 to the original shape thereof. For example, the deformed connecting portion 21 of the PTFE member may be heated to about 300° C.-350° C., to thereby make it recover. Moreover, the connecting portion 21 of the PTFE member 2 may be heated to about 340° C., to thereby make it recover.
It should be understood that the connecting member 1 may also be made of various materials, such as metal, not limited to the materials disclosed above.
In an alternative embodiment, due to high melting temperature of metal, for the connecting member 1 made of metal, the step S103 of heating the polymer member, especially the PTFE connecting portion, may further comprise a step of:
heating the polymer member, especially the PTFE member 2 in an oven, to about 200° C.-350° C., allowing it to recover.
Alternatively, the polymer member 2 may also be made of polyethylene ; for example, polymer member 2 may be made of ultra-high molecular weight polyethylene. Accordingly, the step S103 of heating the connecting portion 21 of the polymer member 2 for shape recovery, may further comprise a step of:
heating the deformed connecting portion 21 of the member 2 made of ultra-high molecular weight polyethylene to about 80° C.-140° C., to thereby make it recover. More specifically, heating the deformed connecting portion 21 to about 90° C.-137° C., to thereby make it recover. More specifically, heating the connecting portion 21 to about 120° C., to thereby make it recover.
In order to improve reliability of the connection between the polymer member 2 and the connecting member 1, for example, as shown in
More specifically, for example, in one of the embodiments of the present disclosure, the connecting member 1 is provided with two connecting members, between which a gap forms a slot 11 for being in interference-fit engagement with the connecting portion 21 of the polymer member 2 after being deformed and heated. The connecting portion 21 may also be applied to seal the gap between the connecting members.
In another embodiment, the slot 11 of the connecting member 1 is provided with a blind hole, which is in interference-fit engagement with and fulfilled with the connecting portion 21 after being deformed and heated. The connecting portion 21 of the polymer member may also be employed as filler so as to fulfill the blind hole, which is not easy to slip out thereafter.
The assembly described in one of the embodiments of the present disclosure may be applied in a medical device, specifically, may be applied in a surgical instrument, particularly an ultrasonic surgical instrument. It will be further described in details as follows by taking PTFE as an example. Similarly, other polymers having the shape memory effect, such as fluorine polymer, polyethylene, ultra-high molecular weight polyethylene etc, also may be applied in one or more embodiments described below.
PTFE is widely used in medical devices due to its chemical properties and low coefficient of friction, for instance, a guiding member of medical catheter. Generally, a guiding member made of PTFE may be designed to be engaged with other members. Etching the PTFE guiding member (e.g. PTFE duct) is a common method of fixing or engaging it with a housing. However, the etching step of method may be omitted by using the method described in one of the embodiments of the present disclosure. For example, the PTFE duct may be deformed so as to be inserted into a rigid housing, and after that, the deformed PTFE duct may be further heated for recovery, such that the duct may be rigid engaged with the housing. Moreover, the PTFE duct may be radially compressed or axially stretched. Besides, the rigid housing may be provided with a rough inner wall or be provided with a plurality of barbs on the inner wall to thereby facilitate the connection therebetween.
In an alternative embodiment, a PTFE member may also be designed as a strip member for being deformed and inserted into a slot or aperture of a member made of other material, such as metal, ceramic or plastic. Reliable engagement between the members may be achieved by heating the deformed PTFE strip member for recovery. The strip member may be, for instance, a tissue pad, or a guiding member with low coefficient of friction for moving a member. In addition, the assembly and assembling method described in one of the embodiments of the present disclosure may be used in other fields where need mechanical engagement of members made of polymer, such as, mechanical equipment, computer mouse, furniture pillar, linear sliding device and surgical instruments. For example, a support pad may be arranged between a wedge and a supporting housing of a linear stapler according to the method of assembling described in one of the embodiments of the present disclosure, so as to decrease friction force therebetween. In one embodiment, at least one PTFE projection integrally formed with the support pad, which may be further engaged with the supporting housing by steps of deforming and heating, as described above. More specifically, the deformed projection may be inserted into a corresponding aperture in the supporting housing, and then be heated to recover so as to be engaged therewith.
Alternatively, the PTFE member may also be designed as a ring member, or a pad for a bearing or a valve. In addition, the assembly of one of embodiments of the present disclosure may also be employed as a sealing member. Therefore, the assembling method and the assembly described in the present disclosure may be applied in many fields, including but not limited to, toys, automobile manufacturing, machining, aerospace, construction, medical equipment, etc.
In another embodiment, the above mentioned assembly may be used in an end effector of an ultrasonic instrument. For example, as shown in
Evidently those skilled in the art can make various modifications and variations to the disclosure without departing from the spirit and scope of the disclosure. Thus the disclosure is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the disclosure and their equivalents.
This application is a continuation of International Application No. PCT/CN2015/086278 filed on Aug. 6, 2015. The entire disclosure of the above application is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2015/086278 | Aug 2015 | US |
| Child | 15837145 | US |
