This invention relates to pivot assemblies for umbrella ribs or struts, such as at a notch or runner.
It is known for a notch or a runner member for an umbrella to be provided with pairs of lugs forming radial slots between which flattened ends of ribs or struts locate, the flattened ends and the lugs being provided with holes through which a wire is threaded to form pivot portions for the ribs or struts, and the ends of the wire being twisted together to secure it in place.
US 904349 (Moulton) discloses a two-part pivot assembly for a notch, where the two parts are held together by a separate spring arrangement in the shaft.
The object of the invention is to simplify the construction and fitting of the pivot assemblies for either notches or runners.
According to the present invention, a pivot assembly for umbrella ribs or struts of the kind having a knob end adjacent a flattened portion comprises a notch or runner in two parts capable of being held together by a locking means and affording in the locked state radial slits, each of which leads to a cavity, so that, in use, the ribs or struts can pivot while the respective knob end is held captive in the cavity, wherein one of the parts is an inner part having a tubular body portion with a bore for fitting closely on an umbrella shaft and an outward annular flange portion adjacent one end of the tubular body portion, the other end of which is divided to form at least two tongues, and the other part is an outer part having a sleeve portion fitting closely on the body portion of the inner part and having an outward annular flange portion engaging the flange portion of the inner part so as to form the cavity for each slit, the slits being provided in one of the flange portions, there being an abutment on the tongues of the inner part for engagement with the sleeve portion of the outer part to prevent them being separated after fitting on an umbrella shaft.
The knob ends of the ribs or struts held captive between the flange portions act as pivots for the ribs or struts, which are guided for swinging by the sliding fit of their flattened portions within the radial slits, from positions alongside the shaft to radial positions. Thus no separate pivot or pivots need to be formed and fitted.
Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which :
In Figures 1 and 3 a pivot assembly 1 for umbrella ribs or struts 2 comprises a notch (Figure 1) or runner (Figure 3) formed by inner and outer parts 3, 4, the inner part 3 having a bore 5 for fitting closely on an umbrella shaft 6 (indicated in broken lines) and an outward annular flange portion 7 adjacent one end of a tubular body portion 8 the other end of which is divided to form two tongues 9, though more could be used, and the outer part (4) having a sleeve portion 10 fitting closely on the body portion 8 of the inner part 3 and having an outward annular flange portion 11 engaging the flange portion 7 of the inner part, one of the flange portions being provided with radial slits 12 each of which leads to a cavity 13 formed between the flange portions.
The ribs or struts 2 each have a knob end 14 adjacent a flattened portion 15 for sliding in one of the radial slits 12 with the knob end held captive in the cavity 13 (see also Figures 2 and 4 in which only one rib or strut 2 is shown for simplicity), there being an engagement between the tongues 9 of the inner part and the sleeve portion 10 of the outer part to prevent them being separated after fitting on to the umbrella shaft 6.
The knob ends 14 of the ribs or struts 2 held captive between the flange portions 7, 11 act as pivots for the ribs or struts, which are guided for swinging by their flattened portions 15 within the radial slits 12, from positions alongside the shaft 6 (as shown at the right of Figures 1 and 3) to radial positions (as shown at the left in those Figures).
In the notch (Figure 1) the radial slits 12 are formed in the flange portion 11 of the outer part 4 and individual cavities 13 for the knob ends 14 are formed by radiating pairs of webs 16 (see Figure 2) across an annular recess 17 in that flange portion. The flange portion 7 of the inner part 3 has a generally U-shaped radial cross-section (minimising material whilst maximising strength) with the base 18 of the U effectively closing the cavities 13 in the flange portion of the outer part, and the outer limb 19 of the U is turned back outwards to form a rebate for location of a rim 20 of the flange portion 11 of the outer part 4.
In the runner (Figure 3) the radial slits 12 are formed in the flange portion 7 of the inner part 3, and individual cavities 13 for the knob ends 14 are formed by radiating pairs of webs 21 (see Figure 4) across an annular recess 22 in that flange portion, the sleeve portion 10 of the outer part 4 has an extension 23 incorporating the usual catch (not shown) in a housing 24 at one side of the extension, and the flange portion 11 of the outer part has a generally U-shaped radial cross section (again minimising material whilst maximising strength) with radial webs 25 providing abutment for the knob ends 14. A narrower U 26 formed round the outside of the flange portion 11 of the outer part 4 forms a rebate for location of rim 27 of the flange portion 7 of the inner part 3.
The engagement between the tongues 9 of the inner part 3 and the sleeve portion 10 of the outer part 4 has a snap action, which is shown provided by outward ribs or « barbs 28 on the tongues being pushed past a portion 29 of reduced diameter inside the sleeve portion, to prevent the two parts 3, 4 being separated after assembly with the ribs or struts 2 and before fitting on the umbrella shaft. Thus the two parts 3, 4 of both notch and runner can be formed conveniently of thermoplastics, and a separate cap or « ornament" 30 (see Figure 5) be provided for the top of the umbrella shaft 6 and the notch after the latter has been secured to the shaft by a pin 31.
The knob end 14 on each rib or strut 2 is conveniently formed by cropping the rod material (from which the ribs and struts are formed) a short distance beyond the end of its flattened portion 15.