Sanitary Clamp Fastener Assembly With Concealed Threads
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Solution Overview
Problem
Sanitary clamps with exposed threads pose a challenge in clean environments as they harbor bacteria and are difficult to clean, despite advancements in hygienic designs for sanitary piping and vessels, which overlook the need for thread concealment to prevent contamination.
Innovation Solution
A threaded fastener assembly featuring a bolt with a smooth shaft and a male-threaded tip, paired with a nut having a blind bore and a seal member to conceal all threads from the ambient, ensuring all surfaces can be cleaned effectively without exposing threads to contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded fasteners (bolts and nuts with exposed threads) are used in sanitary clamps, then the clamp can be easily manufactured and assembled, but the exposed threads harbor bacteria and are difficult to clean, compromising hygiene in clean environments
Solution Approach 1:
The invention extracts the threading function from the external surface of the fastener. The bolt shaft is made smooth and unthreaded externally, while the nut contains all female threads within its blind bore. This separation removes the harmful exposed threads from the sanitary environment while preserving the fastening function.
Solution Approach 2:
The male threads on the bolt tip are nested within the blind bore of the nut, and the entire threaded interface is nested within the nut's internal cavity. The seal member further nests the threaded interface, creating a hierarchical containment structure that isolates threads from the ambient environment.
2Ease of operation
If threads are concealed within the nut's blind bore, then all external surfaces can be cleaned effectively, but the bolt requires a smooth shaft portion and the nut requires a complex blind bore structure
Solution Approach 1:
The bolt is designed with local quality differentiation: a smooth shaft portion for external contact and cleaning, and a threaded tip portion for internal engagement only. The nut has a blind bore with localized threading only where needed, leaving the external surface smooth and cleanable.
Solution Approach 2:
The seal member acts as an intermediary that closes the blind bore of the nut, creating a barrier between the threaded interface and the ambient environment. This mediator allows the threads to exist structurally while preventing their exposure, resolving the conflict between thread functionality and cleanability.
3Reliability
If a seal member is added to close the blind bore, then threads are completely isolated from the ambient, but the fastener assembly requires an additional component
Solution Approach 1:
The seal member is implemented as a thin, flexible sealing element (such as an O-ring or gasket) that closes the blind bore of the nut. This thin film approach provides effective contamination prevention while adding minimal structural complexity and volume to the assembly.
Data Source
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AI summary
A sanitary clamp (110) with facing ring halves employs one or more threaded closure devices configured to avoid having any threads exposed to the ambient. A bolt member (130) may have a stepped shaft with a first smooth shaft portion (126) and a male- threaded tip portion (132). The latter may be the same or a smaller diameter. An associated nut member (128) has a blind bore that extends from a first end of the nut, with a first smooth wall portion (134) and a second female threaded bore portion (136). The second female threaded portion may have the same bore diameter, or the bore can have a stepped interior diameter with the second female threaded bore portion having a diameter smaller than the first smooth wall portion. A seal member or gland (138) within the smooth wall bore portion closes off a space defined between said the tip portion (132) of the bolt member and the female- threaded bore portion (136). Once installed, all threaded surfaces of the bolt member and the nut member that are concealed from the ambient.