WO2016177499A1

WO2016177499A1 - Hose clamp

Info

Publication number: WO2016177499A1
Application number: PCT/EP2016/055510
Authority: WO
Inventors: Martin Hielscher
Original assignee: Norma Germany Gmbh
Priority date: 2015-05-04
Filing date: 2016-03-15
Publication date: 2016-11-10
Also published as: DE102015106910B3

Abstract

The invention relates to a hose clamp having a clamping strip (2) and a clamp housing (4), the clamping strip (2) having an outer-side threaded structure (6). The threaded structure operates with a clamping screw (7) which is mounted in the clamp housing (4). The clamping screw (7) is movably guided in at least one radial direction (10) outwardly against a spring force in the clamp housing (4) for torque limitation.

Description

hose clamp

The invention relates to a hose clamp with a clamp band and a clamp housing with the features of the preamble of claim 1. Hose clamps are used in a variety of ways, in particular for fastening fluid lines to connecting pieces. In this case, the hose clamp is arranged radially outward around the end of the fluid line and tensioned after attaching the fluid line to the connecting piece. For clamping usually serves a clamping screw, which cooperates with its thread in an externally introduced in the clamp band threaded structure. The clamping screw is rotatably but axially fixed in the clamp housing. Accordingly, the hose clamp is contracted or expanded upon actuation of the clamping screw. Such a hose clamp is also referred to as a worm thread clamp. To ensure a fluid-tight connection, a certain minimum tightening torque is required, with which the clamping screw must be tightened. However, this tightening moment too large to prevent damage to the fluid line through the hose clamp. Accordingly, appropriate torque torques are often specified by the manufacturer, which can be met for example by means of a torque wrench.

In order to be able to ensure without torque wrench that the hose clamp or the clamping screw is tightened with the correct torque, solutions are known from the prior art, in which a deformation of the screw head or tearing off a portion of the clamping screw. DE 42 1 1 132 C2 describes a plug-on device for ensuring a predetermined torque when tightening a screw or the like, which has an end section which can be placed on a screw head and a second end section connected to this end section via a predetermined breaking point Type torque application surface is provided. About this device, the screw is screwed with a commercial tool until the second end portion shears from the first end portion at the predetermined breaking point. This is a sign that the screw has been screwed in with the desired torque.

In DE 42 31 003 A1 a clamping screw for a hose clamp is described, which has an inner head part and an outer head part, which are connected to each other via a predetermined breaking point. When a desired tightening torque is exceeded, the outer head part tears off the inner head part. At the inner headboard remains an attack surface for a screwdriver with attack surfaces that are inclined so that a further screwing the clamping screw is not possible, but the clamping screw can be unscrewed.

All these solutions have in common that after reaching or exceeding a predetermined moment, a force transmission element is sheared off and thus lost. A reuse of these devices is not possible. Rather, a new clamping screw is required after each release of the clamping screw before reusing the device. As a rule this leads in connection with hose clamps that the entire hose clamp including clamping screw must be replaced.

The invention is based on the object to provide a hose clamp that allows repeated use, with a defined torque can be limited. According to the invention this object is achieved by a hose clamp having the features of claim 1. Advantageous embodiments can be found in the subclaims.

In a hose clamp with a clamp band and a clamp housing, wherein the clamp band has an external thread structure which cooperates with a clamping screw which is mounted in the clamp housing, the invention provides that the clamping screw in at least one radial direction outwardly guided against a spring force in the clamp housing is. The radial direction refers to a radial direction with respect to the clamping screw. When tightening the hose clamp, the clamping screw only engages with one side of its thread in the threaded structure of the clamp band. Accordingly, acting on the clamping screw on the one hand, an axial clamping force, on the other hand, due to a flank angle of the thread of the clamping screw and / or the threaded structure and a radial force, which endeavors to push the clamping screw from the clamp band radially outward Shen. Contrary to this outward Shen directed radial direction now acts a spring force. When tightening the hose clamp and accordingly further increase in the acting on the clamping screw tightening torque increases not only the clamping force, but also in the radial direction outward acting on the clamping screw force until this force exceeds the spring force. Then the clamping screw moves radially outward Shen, and it comes to skipping a thread. Further tightening the clamping screw is thus prevented. With a suitable choice of the spring force, the clamping screw will thus skip over the thread structure after reaching the desired torque, but before reaching a fractional torque. Thus, the function of a torque clutch is achieved, which is maintained unchanged after repeated actuation. In particular, a loosening and re-tightening the clamping screw is easily possible. Furthermore, there are no sloping parts that need to be collected. This is particularly advantageous in confined spaces or when it comes to high purity advantageous. Preferably, the radial direction extends in the engagement region of the clamping screw in the thread structure perpendicular to the clamp band. A movement of the radial direction perpendicular to the clamp band already allows for a very short distance, namely after exceeding the thread depth, skipping and thus a torque limit. Thus, only relatively little space must be available for the movement of the clamping screw in the radial direction. It is particularly preferred that the clamping screw has a trapezoidal thread. A trapezoidal thread allows for a good interaction with the thread structure of the clamp band, since a thread base can be made relatively wide. Furthermore, a flank angle can be relatively easily set such that corresponding radial forces occur. For example, a preferred flank angle between 45 ° and 60 ° to the groove bottom, which is parallel to the axial direction.

Furthermore, it is particularly preferred that the clamping screw has a fine thread. This is a way by which the hose clamp dissolves in response to the torque limiting by skipping the clamping screw again, kept low. The term fine thread is not strictly to DIN standard to understand, but should generally designate a thread with a low pitch. In a preferred embodiment, a spring element is arranged in the clamp housing, which acts resiliently on the clamping screw. This spring element may be formed, for example, in the form of a leaf spring, which is positioned on the side facing away from the clamp band side of the clamping screw in the clamp housing and rests with bias on the clamping screw.

In an alternative embodiment it is provided that a housing wall of the clamp housing is designed such that it acts resiliently on the clamping screw. This can be achieved for example by a corresponding elasticity in the upper region of the clamp housing, wherein the clamping screw is at least partially in contact with an inner side of the housing wall. This relates in particular to an inside of the housing wall facing away from the spring band clamp.

It is particularly preferred that at least one recess is formed in the side facing away from the clamp band side of the housing wall. A recess or material weakening makes it relatively easy to introduce a targeted elasticity into the clamp housing at the desired location. Thus, a spring force and thus a desired torque can be set relatively accurately.

In a preferred refinement, a plurality of recesses are formed next to one another in the axial direction in the housing wall. With several recesses can be a To achieve more uniform deformation of the clamp housing and thus specify the desired torque more accurately.

The invention will be described in more detail below with reference to a preferred embodiment in conjunction with the drawings. Herein show:

Fig. 1 is a side view of a hose clamp in a partially cut view and

Fig. 2 shows a detail of a hose point in plan view.

FIG. 1 shows a hose clamp 1 with a clamp band 2. At a first end 3 of the clamp band 2, a clamp housing 4 is fixed, through which a second end 5 of the clamp band 2 is passed. On an outer side of the clamp band 2, at least in the region of the second end 5, a thread structure 6 is embossed.

In the clamp housing 4 is a clamping screw 7 with an external thread 8 rotatably and axially fixed so arranged that the Au ßengewinde 8 cooperates with the threaded structure 6 of the clamp band 2. Turning the clamping screw 7 thus causes a further retraction of the second end 5 of the clamp band 2 and thus a contraction of the hose clamp 1 or conveys the second end 5 out of the clamp housing 4, so that the hose clamp 1 is expanded.

On a side facing away from the clamp band 2 side of the clamping screw 7, a spring element 9 is arranged in the clamp housing 4, which exerts a radially inwardly directed force on the clamping screw 7. In the opposite direction, ie in a radial direction 10 to the outside, the clamping screw 7 is movably mounted in the clamp housing 4, wherein in particular a movement corresponding to a thread depth of Au ßengewindes 8 of the clamping screw 7 is possible. By the spring element 9, the clamping screw 7 is pressed against the clamp band, so that the Au ßengewinde 8 usually cooperates with the threaded structure 6 of the clamp band 2.

When tightening the clamping screw 7 occur increasing clamping forces until a desired torque is introduced into the clamping screw 7 and the hose clamp is clamped accordingly. Due to the inclination of thread flanks of Au ßengewindes 8 occur not only clamping forces in the axial direction, which act on the clamping screw 7, but also a force in the radial direction 10, which endeavors to move the clamping screw 7 away from the clamp band 2. As soon as this force exceeds a force of the spring element 9, the clamping screw 7 moves outwards, so that the external thread 8 comes au engagement with the threaded structure 6 au. It comes to a skip over a thread, which prevents further tightening even with an increase of the tightening torque.

Thus, a limitation of the tightening torque is provided via a torque coupling, which allows repeated release and setting of the hose clamp 1 and ensures that even without torque wrench always the required torque can be achieved without the risk of the hose clamp 1 by too strong a moment to overload. The use of a torque wrench can be dispensed with.

FIG. 2 shows a section of the hose clamp 1, in which the clamp housing 4 is designed to be elastically deformable by means of recesses 11 which are inserted in an upper side of a housing wall 12 of the clamp housing 4 facing away from the clamp band 2. On the inside, the clamping screw 7 is directly against the housing wall 12 and causes an elastic deformation as soon as the force acting in the radial direction 10 is sufficient to elastically deform the housing wall 12 until a thread of the clamping screw 7 is exceeded. By this configuration, a torque coupling is achieved without additional elements are required. Rather, the clamp body itself serves as a spring element.

By appropriate choice of the rigidity of the additional spring element or the housing wall, the desired tightening torque can be set relatively precisely, so that a response can be ensured before reaching a fracture torque. In this case, after reaching the desired tightening torque targeted skipping a thread, whereby further tightening is prevented. Rather, a precise tightening the hose clamp is possible even after reopening without torque wrench.

The invention is not limited to one of the above-described embodiments, but can be modified in many ways. For example, the spring element can also be designed as a compression spring. Furthermore, it is conceivable to exploit alone the elasticity of the clamp housing, so that no recesses are required. Also, for example, only a single recess may be sufficient. To get only a small dip in the set clamping force when addressing or skipping a thread, a pitch of the thread should be relatively small. Here, however, can be chosen relatively freely depending on the required application.

The inventive solution no additional component is required, which must be disposed of after tightening the hose clamp. Furthermore, a repeated use of the hose clamp is possible with continued full functionality of the torque limits.

All of the claims, the description and the drawings resulting features and advantages, including design details, spatial arrangements and method steps may be essential to the invention both in itself and in various combinations.

Reference numeral

1 hose clamp

2 clamp band

3 end

4 clamp housing

5 second end

6 thread structure

7 clamping screw

8 outside thread

9 spring element

10 radial direction

1 1 recess

12 housing wall

Claims

claims

1 . Hose clamp with a clamp band (2) and a clamp housing (4), wherein the clamp band (2) has an external threaded structure (6), which cooperates with a clamping screw (7) which is mounted in the clamp housing (4), characterized in that the clamping screw (7) in at least one radial direction (10) outwardly against a spring force is movably guided in the clamp housing (4).

2. Hose clamp according to claim 1, characterized in that the radial direction (10) in the engagement region of the clamping screw (7) in the threaded structure (6) perpendicular to the clamp band (2).

3. Hose clamp according to claim 1 or 2, characterized in that the clamping screw (7) has a trapezoidal thread.

4. Hose clamp according to one of the preceding claims, characterized in that the clamping screw (7) has a fine thread.

5. Hose clamp according to one of the preceding claims, characterized in that in the clamp housing (4) a spring element (9) is arranged, that acts resiliently on the clamping screw (7).

6. Hose clamp according to one of the preceding claims, characterized in that a housing wall (12) of the clamp housing (4) is designed such that it acts resiliently on the clamping screw (7).

7. Hose clamp according to one of the preceding claims, characterized in that in one of the clamp band (2) facing away from the housing wall (12) at least one recess (1 1) is formed.

8. Hose clamp according to claim 7, characterized in that in the housing wall (12) a plurality of recesses (1 1) are formed in the axial direction next to each other.