FI76481C - Shaft bracket for a broom - Google Patents

Abstract

1. A handle attachment for a broom, comprising a broom body (2) having a hollow (4) which extends parallel to the handle (3) and into which can be inserted an adapted pin (6) which is connected with the handle, said pin (6) having a recess (5), a stop (7) and a protrusion (8) which can spring into the recess by manual operation, a retaining edge (9) of the broom body (2) being allocated to the protrusion (8), characterised in that the pin (6) is made of a strip having a U section which has an essentially uniform wall thickness, that the individual legs of the U section merge into one another in a dished manner and are each arched inwards, and that the wall thickness is dimensioned and the U section is adapted to the section of the hollow (4) in such a way that the two lateral legs (10, 11), along their upper ends, and the centre leg (12), in the area of the symmetrical axis, sit in a spring-like manner against the inner wall of the hollow (4), which inner wall otherwise has a space.

Description

1 76481

Broom handle holder

The invention relates to a broom handle fastener formed by a broom body having a recess parallel to the shaft into which a suitable pin connected to the shaft can be inserted, having a recess, a shoulder and a hand-pressable protrusion into the recess, in which a holding body of the broom body is placed.

Such an arm fastener is known from DE-AS 10 29 06 154. The pin for attaching the shaft to the broom body is polygonal in shape and tapered in its protruding part and is made of a thermoplastic material. Due to the design of the pin, different shrinkages are generated in its different areas, which makes it difficult to establish a stationary connection between the shaft and the body of the broom. In addition, most thermoplastically processable materials tend to absorb or release moisture, depending on environmental conditions, which can adversely affect dimensional stability, further complicating the achievement of a stationary fit.

The object of the invention is to develop a broom handle fastener made of a thermoplastic material, which fastener overcomes such difficulties and which is stationary and reliable, especially when the dimensions of the private parts deviate from the ideal dimensions.

According to the invention, this object is achieved in that the pin forms a U-shaped strip, the individual branches of which, when rounded, fit together and each curve inwards, and that the wall thicknesses and U-profile fit to the recess profile are such that the upper and middle parts of both side branches in the center line of symmetry, resiliently rest on the otherwise spaced inner wall-35 of the recess.

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The arm fastener can be made of all properly used thermoplastic raw materials, however, the mechanical, thermal and chemical properties must be taken into account for the dimensioning and the intended use. Due to its low water absorption capacity, the use of polyolefinic substances in the household in particular has proved to be excellent. In contrast, in the field of industrial use, where the stronger effect of organic solvents is to be feared, the use of POM, PETP, PA has proved to be more advantageous.

In the proposed arm fastener, the forces are transmitted to the arm through a branch resiliently resting on the inner wall of the recess of the U-shaped profiled pin. The branches can thus compensate for deviations from the ideal size, and the difficult-to-control dimensional changes resulting from shrinkage 15 or swelling are thus irrelevant.

A prerequisite for this flexible compression, applied to the profile section, is a contact limited to a single point between each branch and the inner wall of the corresponding recess 20. The branches are able to compensate for the irregularities of the intermediate zones in that, in private areas, uniformly nested curvatures result in a smoothed, characteristic cross-sectional load. Voltage cracks between the individual branches of the transition zones in the region 25a are therefore not to be feared.

The mutual distance of the three load application points obtained in one profile section can be made balanced by direction-neutral force conduction and perfectly match each other.

In the case of an ordinary household broom, which has a larger dimension in the transverse direction than in the longitudinal direction, on the other hand, it has proved more advantageous if the distance between the load points of both side arms is greater than the distance of these load points from the corresponding points of the middle branches. The ratio between the two distances in the household broom should be 1.1 ^ -2.5, preferably 1.4.

The pin and the recess are approximately parallel to the shaft, so that mutual contact is not limited to the said three load points, but to the bearing length of the pin corresponding to the through lines. From this, the free dimension has been deducted from the actual length up to the shoulder, which is necessary to ensure the necessary flexibility. In the region of this zone, which terminates immediately in the shoulder or recess opening, the cross-section of the pin has either been reduced so much and / or the cross-section of the recess has been widened so much that mutual contact is excluded. The latter implementation offers an advantage in that the pin, in comparison with the broom arm, has, in addition, a reduced, bearing cross-section in said area.

In order to facilitate the manufacture and to simplify the joining, it has proved advantageous for the protruding part of the pin to be conically tapered, the recess being correspondingly adapted. The degree of conical thinning need only be small, and may be e.g. 1-4 °. The corresponding modification has no effect in principle on the proposed policy.

The ratio of the maximum width and the maximum height of the U-shaped pin should be 1.1-2.1, preferably 1.6. Within said range, the minimum dimensions, i.e. the optimum amount of material, achieve the optimum stability of the broom, the dimension of which is greater in the transverse direction than in the longitudinal direction, with respect to the requirements for anchoring.

30 The curvature of the leg with respect to width A and depth B should be 4.5-7, preferably 5.5. Within said range, there are smoothed stresses applied to the entire cross-section of the pin formed of the U-shaped strip, i.e. there is a particularly high degree of certainty against the occurrence of stress cracks 35 when inserting the pin into the recess of the broom body. Dimension B is defined as an absolute measure of curvature, while dimension A is defined as the reciprocal distance between the outwardly extending points of each branch.

The ratio of the maximum length and the maximum width 5 of the guide pin may be 1.5-3, preferably 2.0. It varies to ensure a special fixed attachment between the shaft and the actual broom body, in addition to easy handling. Both characteristics have a detrimental effect on each other, which is why the proposed area must be considered as a favorable compromise.

The emerging advantages of the proposed shank fastener are, in addition to ease of handling, particularly good reliability, i.e., a fixed attachment between the shank and the broom body, which is highly dependent on the wear phenomena, swelling, shrinkage and inaccuracies of private parts.

The arm clamp can be manufactured at a low cost and proves to be particularly light in weight and quite durable. It is therefore best suited not only for the broom but also for connecting other tools 20 to the arm.

The arm fastener according to the invention will be described with the aid of the drawings in the following appendix. They show: Fig. 1 a longitudinal section of the arm fastener when it is inserted into the recess of the broom body, Fig. 2 the arm fastener according to Fig. 1 in cross-section in the line A-A.

The arm fastener 1 according to Figure 1 is made of a thermoplastic material, namely POM, PETP or PA. It is available in 30 injection molded.

At the top of the arm fastener there is a cylindrical extension 14, on top of which an arm 3 made of thin-walled aluminum / iron tubes is inserted. The leading edge of the arm is surrounded by a protrusion 13 of the arm fastener.

35 The pin 6 extends into the lower area, approximately parallel to the shaft. This is uniformly tapered, both as a whole and to a wall thickness of 5 76481, and thus particularly easy to manufacture and to insert into the recess 4 of the broom body 2.

The pin has a U-shaped recess 5 opened to the right side, into which, starting from the shoulder 7, the spring tongue 15 with its projections 8 extends. This is oblique at the front edge and thus recedes into the recess 5 when the pin 6 is inserted into the recess 4. Due to the subsequent removal of the arm clamp, it is only necessary to press the protrusion 8 into the recess 5 with the thumb 10 and pull the two parts apart towards the bone part. The retaining edge 9 is released in this way.

The recess 4 is expanded in the region of the opening to a free space surrounding the pin, where both parts have no contact with each other. The free space is intended to ensure sufficient transverse movement of the separate branches of the pin 6.

Figure 2 clarifies the geometrical position of the interconnected parts according to Figure 1 in the plane of the section line A-A.

20 Pin 6 has a U-shaped profile, the three branches of which curve inwards and, while the wall thickness remains the same, are rounded together.

The cross-section of the recess 4 of the broom body 2 is approximately adapted to the cross-section of the pin, however, the latter is surrounded at a distance in cross-section by the load points C. The private branches 10, 11, 12 of the pin can thus move freely between load points C and thus compensate for dimensional deviations. The load points clarify the position of the contact lines 30 parallel to the shaft and thus perpendicular to the drawing plane between the pin and the recess of the broom body.

The transmission in the area of the contact lines takes place, depending on the actual load, approximately in the direction of the vectors shown in Fig. 2 35, i.e. corresponding to the conditions of a statically stable force triangle.

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Thus, ways of loading the broom shaft in which loosening is to be feared cannot occur.

The magnitude of the curvatures of the profile branches 10, 11, 12 of the pin 6 is determined by dimensions A and B. Dimension A determines the distance of the 5 outermost points, dimension B the vertical distance of a point on the same surface, which surface collapses furthest rearward, both measured in unloaded condition.

Claims (9)

1. A shaft bracket for a broom, consisting of a broom body (2) having a recess (4) parallel to the shaft (3), in which a pin (6) connected to the shaft can be inserted, said pin having a recess (5), a stop (7), and a resilient protrusion (8) by means of manual actuation into the recess (5), with which is coordinated a pouring edge (9) on the brush body, characterized in that the pin (6) consists of a U-shaped profile strip, the individual legs of which are rounded over each other and are arched in mesh, and that the dimensioning of the wall thickness and the adaptation of the U-profile to the recess (4) is carried out so that both side legs ( 10, 15) along its upper ends and the center leg (12) in the region of the axis of symmetry resiliently abuts the otherwise inner wall of the recess (4). Shaft bracket according to claim 1, characterized in that the ratio of the maximum width of the U-profile 20 to its highest height is 1.1-2.1. 3. Shaft bracket according to claims 1 and 2, characterized in that the ratio between the maximum width of the U-profile and the highest height is 1.6. 4. Shaft bracket according to claim 1, characterized in that the ratio between the width A and the depth B of the indentations on the legs is up to 4.5-7, measured in an unstressed condition. 5. A shaft bracket according to claims 1-4, characterized in that the ratio between the width 30 (A) and the depth (B) of the indentations of the legs is up to 5.5, measured in unstressed condition. 6. A shaft bracket according to claims 1-2, characterized in that the profile of the pin in the protruding part tapers evenly. 7. A shaft bracket according to claims 1-6, characterized in that the relationship between the control pin