Castor with brake and locking mechanism

A caster is provided with two braking mechanisms and/or a locking mechanism. One embodiment of the present invention provides a castor including a wheel having an axis of rotation and a mounting bracket for a load. A brake lever is attached to the wheel adjacent the axis of rotation and pivotally attached to the mounting bracket. The brake lever is movable to selectively place the wheel and mounting bracket in a locked position or a rotation position. A first brake surface is associated with the mounting bracket and contacts the wheel when the wheel is in the locked position to substantially restrict wheel rotation. A second brake member, having a second brake surface, is linked to the mounting bracket and the brake lever so that the second brake surface contacts the wheel when the wheel is in the locked position. In an alternate embodiment, a lock mechanism is associated with the castor and is selectively engagable to restrict the wheel from moving from the locked position to the rotation position. A preferred embodiment includes a second brake member and a lock mechanism.

FIELD OF THE INVENTION
 The present invention relates to a castor for scaffolding, equipment, or
 other loads. More particularly, the present invention relates to locking
 and braking mechanisms for a castor.
 BACKGROUND OF THE INVENTION
 Frequently, it is desirable to have equipment or heavy loads mounted on
 castors or wheels for mobility while maintaining the ability to fix the
 load in place. Construction scaffolding is an example of such a use where
 assembly and use of the scaffolding may first occur in one location, but
 thereafter it is desired to move the scaffolding to a new location without
 spending the time or effort necessary to disassemble and reassemble it.
 Traditionally, there have been safety concerns regarding scaffolding or
 loads on wheels since such constructs are prone to wobble and/or movement
 if not braced or anchored. To counteract this it is desirable to stop or
 substantially restrict rotation of the wheels to provide the necessary
 stability.
 One attempt to address this problem is discussed in U.S. Pat. No. 5,829,096
 issued to Eugene Perry. The Perry patent illustrates a typical prior art
 castor consisting of a wheel, a load bracket, a foot lever, and one brake.
 In a typical prior art castor, the operator steps on the foot lever to
 transpose the load over the center of the wheel. This movement brings the
 wheel into contact with the brake, where resistance and inertia may
 restrict movement of the wheel.
 There remains a need for a castor which can safely and selectively restrict
 movement of the wheel to provide improved load stability.
 SUMMARY OF THE INVENTION
 A caster is provided with two braking mechanisms, a locking mechanism or a
 combination thereof. One embodiment of the present invention provides a
 castor including a wheel having an axis of rotation and a mounting bracket
 for a load. A brake lever is attached to the wheel adjacent the axis of
 rotation and pivotally attached to the mounting bracket. The brake lever
 is movable to selectively place the wheel and mounting bracket in a locked
 position or a rotation position. A first brake surface is associated with
 the mounting bracket and contacts the wheel when the wheel is in the
 locked position to substantially restrict wheel rotation. In one
 embodiment, a second brake member, having a second brake surface, is
 linked to the mounting bracket and the brake lever so that the second
 brake surface contacts the wheel when the wheel is in the locked position.
 In an alternate embodiment, a lock mechanism is associated with the castor
 and is selectively engagable to restrict the wheel from moving from the
 locked position to the rotation position. A preferred embodiment includes
 a second brake member and a lock mechanism.
 It is one object of the present invention to provide an improved castor.
 Further objects, features and advantages of the present invention shall
 become apparent from the detailed drawings and descriptions provided
 herein.

DESCRIPTION OF PREFERRED EMBODIMENTS
 For the purposes of promoting an understanding of the principles of the
 present invention, reference will now be made to the embodiments
 illustrated and specific language will be used to describe the same. It
 will nevertheless be understood that no limitation of the scope of the
 invention is thereby intended, such alterations, modifications, and
 further applications of the principles of the invention being contemplated
 as would normally occur to one skilled in the art to which the invention
 relates.
 The present invention provides a castor for use with equipment or other
 heavy loads such as scaffolding. When in a locked position, the present
 invention increases stability of the load by restricting movement of the
 wheel. In some embodiments, movement is restricted by providing additional
 braking surface engaging the wheel. Alternate embodiments of the present
 invention provide a lock to prevent unintended movement of the wheel from
 a locked position to a rotation position.
 One preferred embodiment of the present invention is illustrated with
 castor 10 in an unlocked position in FIG. 1 and in a locked position in
 FIG. 2. Castor 10 includes wheel 12, mounting bracket 20, and brake lever
 30. Wheel 12 has axis of rotation R where it is rotatably mounted to brake
 lever 30 by axle bolt 14. Brake lever 30 is pivotally connected to
 mounting bracket 20 at pivot-points 22 with rivets or other connectors on
 either side of castor 10. Load bearing means 16 such as a stem, pole or
 other attachment is oriented on mounting bracket 20 and defines load
 bearing axis B through load bearing means 16 and mounting bracket 20. Load
 bearing means 16 may optionally be free to rotate on bracket 20. Castor
 axis C extends in a line which intersects axis of rotation R and a line
 extending through pivot points 22. Axis C pivots about pivot points 22 as
 castor 10 and wheel 12 are moved between a locked and an unlocked or
 rotation position.
 Mounting pin 26 extends through opposing openings in mounting bracket 20
 and couples first brake member 40 (FIG. 5) to mounting bracket 20.
 Mounting pin 24 extends through opposing openings in mounting bracket 20
 and pivotally couples second brake member 50 and locking member 60 to
 mounting bracket 20. Second brake member 50 extends from bracket 20
 linking mounting bracket 20 and brake lever 30 via sliding pin 37. Pin 37
 is mounted to brake lever 30 and extends through slots 57 in second brake
 member 50. Second brake member 50 includes second braking surface 52 (FIG.
 4). Brake lever 30 includes foot pedal 33.
 FIGS. 3 and 4 illustrate partially cut away views of castor 10 in unlocked
 and locked positions respectively. A left front, wheel-on view of castor
 10 is illustrated in FIG. 5. First braking member 40 includes first
 braking surface 42, and second braking member 50 includes second braking
 surface 52. In FIG. 3, foot pedal 33 is raised in relation to mounting
 bracket 20 which moves wheel 12 away from first braking surface 42 and
 second braking surface 52. When foot pedal 33 is lowered in relation to
 mounting bracket 20, as illustrated in FIG. 4, it transposes load bearing
 axis B substantially into intersection with axis of rotation R of wheel
 12, placing wheel 12 in contact with first braking surface 42.
 In one embodiment, sliding pin 37, extending through break lever 30, is
 slidably received in slots 57 defined in second braking member 50. When
 foot pedal 33 is lowered, it moves second braking member 50 such that
 second braking surface 52 contacts wheel 12.
 In a further embodiment, when castor 10 is in a locked position, locking
 member 60 (described below) cooperates with second braking member 50 to
 selectively keep castor 10 from moving to an unlocked position. In one
 embodiment, the sidewalls of locking member 60 nest between the sidewalls
 of second brake member 50.
 FIGS. 6A and 6B illustrate side and front views of mounting bracket 20. In
 one embodiment pivot points 22 are punched, drilled or otherwise cut in
 bracket 20, and are pivotally attached to brake lever 30 when the castor
 is assembled. Rivets, bolts, pins or other pivot connections can be used.
 Bracket 20 also includes holes for mounting pins 24 and 26. Opposing
 dimples or protrusions 28 which extend towards brake lever 30 may
 optionally be formed in bracket 20.
 Brake lever 30 is illustrated in FIGS. 7A, 7B, and 7C. For illustration
 purposes a flat of brake lever 30 is illustrated in FIG. 7A, prior to
 being symmetrically bent to the tapered form shown in FIGS. 7B and 7C.
 Brake lever 30 includes foot pedal 33, axle or wheel pivot openings 34 for
 axle bolt 14, mounting or pivot points 32 for connection to mounting
 bracket 20, and optional stop openings 38. Stop points 38 and dimples 28
 are located in an area of overlap between mounting bracket 20 and brake
 lever 30. Opposing stop points 38 may be punched or drilled through brake
 lever 30 or may be recessed dimples which cooperate to receive dimples 28
 of mounting bracket 20 when castor 10 is in an unlocked position. Optional
 stop openings 38 and dimples 28 cooperate to yieldingly maintain caster 10
 in an unlocked position until an operator purposefully switches caster 10
 to a locked position.
 First braking member 40 is illustrated in front and flat views in FIGS. 8A
 and 8B. First braking member 40 includes first braking surface 42 and
 sidewalls 44. A braking pattern such as indented or raised portions 43 may
 be placed on first braking surface 42 and/or second braking surface 52.
 Example braking patterns may be an "X" as shown, circular or curved
 portions, and/or parallel or intersecting line segments.
 One embodiment of second braking member 50 is illustrated in FIGS. 9A and
 9B. Second braking member 50 is formed with second braking surface 52, has
 one or more sliding slots 57 in the sidewalls, and has mounting holes 59
 for mounting pin 24. As discussed above, a pattern may optionally be
 formed on second braking surface 52. In an alternate embodiment, second
 braking surface 52 formed with a concave surface to engage a larger
 surface area of wheel 12 when castor 10 is locked. Sliding pin 37 in brake
 lever 30 is received in slots 57 and travels within slots 57 when caster
 10 is moved between a locked and an unlocked position. Sliding pin 37
 alternatively is solidly attached or formed as a retaining portion of
 brake lever 30.
 FIGS. 10A and 10B illustrate perspective and side views of locking member
 60. Locking member 60 is mounted to mounting bracket 20 by mounting pin 24
 which extends through mounting holes 69 in addition to mounting holes 59.
 When castor 10 is in an unlocked position, sliding tracks 63 rest atop
 sliding pin 37. When castor 10 is moved to a closed position, sliding pin
 37 slides along sliding track 63, around tab 62 and is received into
 defined holding slots 64 transverse to sliding pin 37. Once engaged in
 holding slots 64, sliding pin 37 is held by tabs 62 from sliding back
 until locking member 60 is lifted by handle 61. Alternatively, locking
 member 60 may terminate in a tab or flange which abuts sliding pin 37 when
 engaged, or locking member 60 includes holding flanges or tabs 62 which
 abut sliding pin 37 to lock it in position without flanges or tabs on the
 opposite side of sliding pin 37.
 In operation, one or more castors 10 are deployed for a load, such as
 scaffolding, during assembly. Prior to movement the castor is placed in an
 unlocked or wheel rotating position, allowing the wheel to rotate and/or
 the castor to pivot to allow the load to be rolled to a desired location.
 Once in place, the operator step pivot points 22 on foot pedal 33 of brake
 lever 30 shifting the load around the fulcrum of pivot points 22 and
 pivoting castor axis C so that load bearing axis B of mounting bracket 20
 is transposed over wheel 12 and intersects or slightly passes rotational
 axis R. During each movement from a rotation to a locked position, or the
 reverse, load bearing axis B intersects axis of rotation R of wheel 12
 once. When first brake member 40 contacts wheel 12, it prohibits further
 rotation of caster axis C.
 Once shifted, wheel 12 is in contact with first braking surface 42 to
 substantially restrict wheel rotation. Concurrently, as brake lever 30
 pivots caster axis C, brake lever 30 and sliding pin 37 apply a transverse
 force in slots 57 against brake member 50 bringing second brake surface 52
 into contact with wheel 12 supplying additional resistance to wheel
 rotation.
 In an alternate embodiment, brake lever 30 can be rotated so that load
 bearing axis B is transposed past axis of rotation R when locking castor
 10. In this embodiment, load bearing axis B applies additional force to
 first brake member 40 by leverage, further restricting wheel movement and
 providing additional stability. The more load bearing axis B is moved past
 rotational axis R the more difficult it is to unlock caster 10 since load
 bearing axis B must be returned across axis of rotation R without the
 leverage benefit of brake lever 30.
 In one embodiment, when the operator fully locks caster 10, holding slots
 64 of locking member 60 receive sliding pin 37 and transverse tabs 62 abut
 sliding pin 37. Sliding pin 37 is thus held to prevent brake castor 10
 from returning to an unlocked position until released. When unlocking is
 desired, handle 61 of locking member 60 is lifted, releasing sliding pin
 37 from slot 64 and allowing sliding pin 37 to travel in slot 57 of second
 braking member 50, thus removing wheel 12 from contact with the braking
 surfaces.
 For purposes of illustration, wheel 12 may be made from a durable rubber,
 or may be metal or stone as commonly understood in the industry.
 Similarly, brake lever 30, mounting bracket 20, first brake member 40,
 second brake member 50 and/or locking member 60 may be punched, stamped,
 cast, cut, molded, extruded or made using known methods from metal,
 plastic or other durable materials having sufficient strength. The pieces
 may be formed with appropriate openings and then bent or shaped into the
 desired forms using methods which are standard in the industry.
 Optionally, instructional indicia such as arrows, and/or the word "lock"
 may be engraved, stamped, or labeled on the components.
 While the invention has been illustrated and described in detail in the
 drawings and foregoing description, the same is to be considered as
 illustrative and not restrictive in character, it being understood that
 only preferred embodiments have been shown and described and that all
 changes and modifications that come within the spirit of the invention are
 desired to be protected.