GB1331215A - Clamping devices for castors on movable apparatus - Google Patents

Abstract

1331215 Castors HAPPE & CO 19 May 1972 [21 May 1971] 23649/72 Heading A4U [Also in Division F2] A clamping device, for castors 6 mounted on two adjacent tubular legs 1, 2, (e.g. of an invalid chair), connected by transverse means 3, comprises two holding means 14 each operative to hold a respective castor against motion, two elements 22 each reciprocable axially within a respective leg 1 or 2 and each biased axially by a spring, motion of the element in one direction effecting application of the associated holding means, and motion in the other direction effecting release, two link pins 25 each connected to a respective one of the elements 22 and extending through a longitudinally extending slot 26 in the wall of the associated leg, and a rod 28 manually operable to cause sliding of the link pins in the slots and thus cause movement of the elements in one of the directions, the rod having a position external of the connecting means 3 such that inadvertent motion of rod 28 is prevented by the connecting means. In Figs. 1 to 4, legs 1, 2 are connected by a transverse stay 3, each leg having within it a reciprocable element 22 having connected to it a link pin 25 extending through a slot 26. A rod 28 having two levers 29 is connected by crank webs 27 to the pins 25. In each leg a spring 23 urges, through the element 22, a bolt 13 downwards to tilt further a Z-shaped curved plate 14 from the Fig. 2 position. In Fig.2, pin 25 is held near the top of its slot by engagement of rod 28 at A and lever 29 at B, respectively, with a ring 30 surrounding the stay 3, past a dead-centre position. When lever 29 is moved upwards to the Fig. 3 position, spring 23 urges element 22 and bolt 13 downwards, so part 14'of plate 14 raises plate spring 16 so that its free end 16' engages toothed plate 21, preventing castor swivelling, and lowers plate spring 17 so that spring 17 brakes wheel 6. Stop pin 31 assists alignment of cross-bore 22' and pin 25 during assembly. In Figs.5 to 7, (not shown), spring 23 is below element 22 and acts upwards for release. Rod 28 is also below stay 3, and lever 29 is pivotted downwards to reach the release position: a radial plug (29") is provided at each end of rod 28 to engage stay 3 in the release position. In Fig. 9, spring 23 acts downwards to apply the brake; each lever 29 has a side member 33 formed integral with it, and to the side member is pivotted at 35 a semi-circular link 34 connected to pin 25. Each lever is itself pivotted about stay 3, so rod 28 describes an arc around the stay between positions. In the release position, Fig.8, (not shown), pivot 35 is located past the top-deadcentre position of link 34, so spring 23 maintains this position via element 22 and pin 25; the inside of link 24 engages stay 3. In Figs. 11 and 12. "rod" 28 actually surrounds stay 3 except at the ends (see Fig. 12) so that there the link 34 can contact the stay in the release positon.