Parking brake for twin wheels

Abstract: The brake for twin wheels cantilevered rotatably on a support member (3) comprises a forked support member (6), a pedal (10) with an operating portion (12) projecting from the support (6) and a cam-shaped drive portion (14) located within the support (6), the pedal (10) being pivotable between a rest position and an operative position, and a coaster brake (16) articulated to the support (6), pivotable by the cam portion (14) of the pedal (10) as a result of the pivoting thereof, and having a portion (20) which is arranged to interfere with the wheels (4) as a result of its pivoting in order to stop the wheels (4). The brake also includes a resilient element (22) which, in the rest position, keeps the coaster brake (16) spaced from the wheels (4), and a small pedal (26) which, in the rest position, is inserted in a seat (24) within the support (6) and which has an operating portion (27) and a slot (28) in which the hook-shaped end (30) of the control portion (14) of the pedal (10) is inserted. The operation of the pedal (10) causes the removal of the small pedal (26) from its seat (24), whilst the operation of the operating portion (27) of the small pedal (26) causes the reinsertion of the small pedal (26) in its seat (24) and the pivoting of the pedal (10) into its rest position, with the consequent release of the coaster brake (16) from the wheels (4).

Description: The present invention relates to a parking brake for twin wheels according to the pre-characterising portion of claim 1. In FR-A-2 098 293 it is disclosed a parking brake for a single wheel having the above features, wherein the coaster brake is articulated by its middle portion to the support member. Therefore during the braking action the two end portions of the coaster brake contact respectively the wheel and a braking surface of a bearing for the connection between the support member and the frame of a trolley, on which the wheel is assembled. During the braking action, large and possibly harmful forces may therefore be transmitted to the bearing. The object of the present invention is to provide a parking brake for a pair of twin wheels which is simple to produce and easy to operate. This object is achieved by means of a parking brake further provided with the features disclosed in the characterising portion of claim 1. The advantages and characteristics of the present invention will become clear from the following detailed description, given with reference to the appended drawings, provided by way of non-limiting example, in which: Figure 1 is a perspective view of a parking brake according to the invention in the rest position and mounted on a pair of twin wheels of a trolley, Figure 2 is a perspective view of the brake of Figure 1 in the operative position, Figure 3 is a section taken on the line III-III of Figure 1, and Figure 4 is a perspective view of the brake according to the invention. With reference to the drawings, a trolley 2 has a pair of twin wheels 4 cantilevered rotatably on a support member 3 having a vertical portion 5 and a horizontal portion 7 coaxial with the axle 8 of the wheels 4. A parking brake for the wheels 4 includes a forked support member 6 constituted by a cross-member 6a from beneath which project two arms 6b which have holes 9 for receiving the portion 7 of the support member 3. A pair of facing, apertured projections 11 is formed around the hole 9 of at least one of the arms 6b for the insertion of a resilient pin 13 for fixing the fork 6 to the horizontal portion 7 of the support member 3 in a position in which it is inclined to the vertical. The parking brake further includes a pedal 10 having an operating portion 12 projecting from the support 6 near the cross-member 6a and a cam-shaped drive portion 14 within the support 6. The pedal 10 can pivot between a rest position (shown in Figure 1) and an operating position (shown in Figure 2). A coaster brake 16 which is articulated, or at any rate pivoted at 15, on the support 6, is pivotable by the cam portion 14 of the pedal 10 and has two arms 18 which extend outside the support 6, parallel to the axle 8, for interfering with the wheels 4 so as to lock them as a result of the pivoting of the coaster brake. The regions of the arms 18 which will come into contact with the wheels 4 may have linings 20 of anti-friction material. A wire spring 22 keeps the arms 18 of the brake 16 spaced from the wheels 4 in the rest condition of the brake. In alternative embodiments of the invention, not illustrated, it is possible to use a leaf spring instead of the wire spring 22. The support 6 has a seat 24 in which a small pedal 26 is inserted when the brake is in the rest condition, the small pedal 26 having an aperating portion 27 and a slot 28 in which a hook-shaped end 30 of the drive portion 14 of the pedal 10 is inserted. To change from the rest configuration (shown in Figure 1) to the braking configuration (shown in Figure 2), it is necessary to pivot the pedal 10 by acting on its operating portion 12. The cam-shaped portion 14 of the pedal 10 thus makes the coaster brake 16 pivot about the hinge 15 to bring the anti-friction linings 20 of the arms 18 into contact with the wheels 4 and thus stop them. As the pedal 10 pivots, the hook-shaped end 30 simultaneously moves the small pedal 26 out of its seat 24. In order to return from the braking configuration to the rest configuration, it suffices to act on the operating portion 27 of the small pedal 26 to return it, by a translational movement, into its seat 24. During this movement, the pedal 10 pivots in the opposite sense from its previous pivoting as a result of the engagement between its hook-shaped end 30 and the slot 28 in the small pedal 26, and releases the coaster brake 16 which returns to the rest position under the action of the spring 22, releasing the wheels 4.

Claims: A parking brake for twin wheels (4) cantilevered rotatably on a support member (3), comprising: a forked support member (6), a pedal (10) with an operating portion (12) projecting from the support (6), the pedal (10) being pivotable between a rest position and an operative position, a coaster brake (16) articulated on the support (6) and pivotable by the pedal (10) as a result of the pivoting thereof, the brake (16) having a portion (20) which is arranged to interfere with the wheels (4) as a result of its pivoting in order to stop the wheels (4), a resilient element (22) which, in the rest position, keeps the coaster brake (16) spaced from the wheels (4), and a small pedal (26) connected to the pedal (10) for releasing the interfering portion (20) of the coaster brake (16) from the wheels (4), said parking brake being characterised in that the pedal (10) has a cam-shaped drive portion (14) located within the support (6) and able to cause the pivoting of the coaster brake (16), the coaster brake (16) is articulated on the support (6) by an end portion opposite to the portion (20) arranged to interfere with the wheels (4), and the small pedal is, in the rest condition, inserted in a seat (24) within the support (6) and has an operating portion (27) and a slot (28) in which the hook-shaped end (30) of the drive portion (14) of the pedal (10) is inserted, the operation of the pedal (10) causing the removal of the small pedal (26) from its seat (24) and the operation of the operating portion (27) of the small pedal (26) causing the reinsertion of the small pedal (26) in its seat (24) and the pivoting of the pedal (10) into its rest position with the consequent release of the coaster brake (16) from the wheels (4). A parking brake according to Claim 1, characterised in that the portion of the coaster brake (16) which is arranged to interfere with the wheels (4) is constituted by two arms (18) which extend outside the fork (6), substantially parallel to the axle (8) of the wheels (4). An operating brake according to Claim 2, characterised in that the arms (18) have linings (20) of anti-friction material in their regions intended to contact the wheels (4). A parking brake according to Claim 1, characterised in that the resilient element is constituted by a wire spring (22). A parking brake according to Claim 1, characterised in that the resilient element is constituted by a leaf spring. A parking brake according to any one of the preceding claims for twin wheels cantilevered rotatably on a support member (3) having a horizontal portion (7), the brake being characterised in that the forked support member (6) is constituted by a cross-member (6a) from beneath which extend two arms (6b) which have respective holes (9) for receiving the horizontal portion (7), a pair of facing, apertured projections (11) being formed around at least one of the holes (9) for the insertion of a resilient pin (13) for fixing the support (6) to the horizontal portion (7) of the support member (3) in a position in which it is inclined to the vertical.

Inventors: SANTACHIARA ANDREA, SANTACHIARA, ANDREA
Applicants: TELLURE ROTA SPA, TELLURE ROTA S.P.A.
Application year: 1990
Main classification: B60B33
IPC codes: B60B33