The invention relates to the field of hand trucks, and a braking device for hand trucks.
The invention comprises a hand truck braking device. The braking device comprises a brake actuator which is positioned within reach of the handle of the hand truck, a connector preferably in the form of an upside down Y-shaped cable, and a brake paddle having a lever portion, a pivot and a brake portion. The connector preferably attaches the actuator to each brake element directly, with the tail end of the Y cable attached to the brake actuator and each arm of the Y cable attached to a brake paddle element on one side of the hand truck. The arms connected to the brake paddle elements connect to the lever arm of the brake paddle such that when tension is applied to the cable the paddle break pivots, therefore applying pressure at the brake end of the brake paddle to the wheel.
A hand truck 20 according to the preferred embodiment described herein comprises a frame 22, wherein frame 22 comprises a handle 24 for the user, connected on each side to side rails 26 (
A brake actuator mounting bracket 42 is affixed to each side rail 26 to attach brake actuator 50 to frame 22. Each brake actuator mounting bracket 42 extends rearwardly from each side rail 26, and includes a hole 46 therethrough for receiving the ends of brake actuator 50. Each brake actuator mounting bracket 42 is preferably formed in a single piece which is mountable on a side rail 26. Brake actuator 50, which is mounted to the hand truck 20 via mounting brackets 42, comprises a brake actuator handle 52, preferably formed of wire rod, bent to define spaced lever portions 54 extending rearwardly from side rails 26, which join with spaced generally vertical portions 56, which in turn join a hand grip 58 which extends between the upper ends of vertical portions 56. Hand grip 58 is located high enough on the frame so that the average user of hand truck 20 does not have to bend to reach hand grip 58. Preferably, hand grip 58 is located within hand's reach for the user of handle 24.
Each brake actuator lever 54 is bent inwardly at its end, such that the inwardly extending ends extend through holes 46 in mounting brackets 42, at about a right angle thereto, thereby pivotally mounting actuator handle 52 to mounting brackets 42 (
When we say that lever portions 54 extend rearwardly from side rails 26 in a plane generally perpendicular to side rails 26, we intend to allow form some latitude from 90°, e.g. plus or minus 15°. Lever 54 provides leverage for the operation of braking device 40 when handle 52 is grasped by the user and pulled upwardly toward handle 24.
Brake actuator 50 further comprises a cross bar 60 extending between the two sides of the brake actuator handle 52, preferably at a point spaced rearwardly about as far as possible from the side rails 26 in order to maximize leverage. Preferably, it is located at or near the juncture of lever portions 54 and upwardly extending portions 56. Brake actuator crossbar 60 is fitted with an actuator cable mount 62 near the center thereof (
On the bottom portion of frame 22, near where wheels 30 are mounted, a brake paddle mounting bracket 70 is provided on each side rail 26 of frame 22, one on the right side rail 26, and one on the left side rail 26. Each brake paddle mounting bracket 70 has a portion extending rearwardly from side rail 26, with a hole 72 therethrough. Brake paddle mounting bracket 70 is preferably a single piece, and may also be formed to be symmetrical, so that one form of bracket 70 can be used on the right side and flipped upside-down to be used on the other side. An axle 74 extends across the back of frame 22 and through hole 72 in each mounting bracket 70, and extends outward beyond the side rails 26, preferably terminating above wheels 30.
One brake paddle 80 is pivotally mounted to each end of axle 74, and the brake paddles 80 are positioned so as to allow each brake paddle 80 to come into contact with a wheel 30 when braking device 40 is actuated by the user (
Each brake paddle 80 comprises a lever element 88 on one side of the pivotal mount and a braking element 90 on the other side of the pivotal mount. The legs of the Y-cable 66, 68 are mounted via a brake cable mount 92 to levers 88 of right and left brake paddles 80, respectively. Lever 88 increases the force applied by braking element 90 when braking device 40 is actuated by the user. Lever 88 is preferably integral with and extends rearwardly from the interior side flange 82 (the one located toward the center of frame 22) of the brake paddle 80, to prevent interference with frame 22 (
Between the side flanges 82 of brake paddle 80, a wide paddle member 94 is generally oriented so as to be tangential to the outer surface of wheel 30. (
When brake actuator handle 52 is lifted by the operator to come into closer contact with handle 24, brake actuator crossbar 60 is also raised, which pulls Y cable 64 in an upward direction, transferring the force to the right and left legs 66, 68 of Y cable 64. The motion of right and left legs of Y cable 66, 68 lifts lever element 88 of brake paddle 80. The pivotal mounting of brake paddle 80 means that each braking element 90 of brake paddle 80 is rotated downwardly so that braking surface 96 is brought into contact with wheels 30 when lever 88 is lifted by an upward force on Y-cable 64. Due to the use of a Y-shaped cable 64 having a short upper cable length 65 coupled to right leg 66 and left leg 68, and due to the individually pivotal brake paddles 80, brake paddles 80 are permitted to apply force evenly to wheels 30 even if there is some unevenness of wear or inflation or other potential inconsistency between each of the wheels 30. This self equalization of brake force is achieved because the flexible upper cable 65 is free to swing right or left slightly, allowing the cable coupling member 65a to shift left or right in response to what would otherwise be unequal tension on cable legs 66 and 68. It is important that upper cable portion 65 be of sufficient length to allow this side to side brake force equalizing swinging motion.
Location and placement of the brake actuator handle 52 permits the operator of hand truck 20 to easily brake or apply light pressure to the brakes to slow moving hand truck 20 or to lock hand truck 20 into position.
The hand grip portions 58a of brake actuator handle 52a extend rearwardly from the upwardly extending portions 56a, and thus are an extension of portions 54a. In this embodiment, the leverage applied by squeezing hand grip portions 58a upwardly towards handles 24a is converted to pivotal motion, which is conveyed to brake cable 64 through lever arm 59a. Lever arm 59a is the “lever” portion of the actuator handle 52a of this embodiment, which acts directly through brake cable 64 on brake paddles 80. As with the first embodiment hand truck 20, location and placement of the brake actuator handle 52a permits the operator of hand truck 20a to easily brake or apply light pressure to the brakes to slow moving hand truck 20a or to lock hand truck 20a into position.
In this embodiment, the leverage applied by squeezing hand grip 58b upwardly toward handle 24b is converted to pivotal motion, which is conveyed to brake cable 64 through pivot lever arm 59b. Lever arm 59b is the “lever” portion of the actuator handle 52b of this embodiment, which acts directly through brake cable 64 on brake paddles 80. As with the first and second embodiments of hand trucks 20, 20a, location and placement of the brake actuator handle 52b permits the operator of hand truck 52b to easily brake or apply light pressure to the brakes to slow moving hand truck 20b or lock hand truck 20b into position.
Of course it is understood that the above is a description of preferred embodiments, and that various changes and alterations can be made to the hand truck 20 and braking device 40 without departing from the spirit and broader aspects of the invention.