Cam actuated brake mechanism for adjustable beam trolley

A brake mechanism for a beam trolley on a beam has a body member on the beam trolley adjacent the beam. The body member has a recess and axially aligned bores and a rotatable lateral pin extends through the aligned bores. The lateral pin has a rotatable elongate cam portion extending across the recess, and a brake pad is in the recess adjacent to the beam and abutting the cam portion. A handle is connected to the lateral pin for rotating the pin and the cam portion to displace the brake pad against the beam. The brake pad frictionally secures the beam trolley on the beam and locks the rotatable cam in place. Rounded end portions on opposite ends of the lateral pin and sleeve-like bushings between the axially aligned bores and rounded end portions permit rotation of the cam portion by the handle.

BACKGROUND OF THE INVENTION

This invention is for securing a beam trolley on an I-beam or H-beam. More particularly, this invention is to a adjustable width beam hoist trolley having a manually activated friction brake to selectively and safely secure a loaded or unloaded beam trolley at a selected position along the length of the beam.

Adjustable beam trolleys are industry standard devices for permanent or temporary mounting of a hoist on a standard I-beam or H-beam. The beam trolleys provide vertical support and permit linear motion of the supported load as the trolley rolls along the length of the beam. Many adjustable beam trolleys are commercially available from a number of manufacturers and are called adjustable because they can be adjusted to accommodate differently sized I and H beams.FIGS. 1 and 2show a typical commercially available adjustable beam trolley10having a pair of steel side plates11shaped with end-bumpers12, and each side plate11mounts a pair of load bearing trolley wheels13on steel axles14. A heavy-duty threaded steel bolt15, having secured end-nuts16abutting the outsides of side plates11, laterally extends through round openings (not shown) provided in both of side plates11and aligned bores (not shown) in inward extensions17of side plates11. A steel load bearing hoist mount18is mounted midway on threaded bolt15where it extends between inward extensions17to receive and support a manual or automatic chain hoist connected to a load (not shown).

FIG. 2shows in greater detail that an appropriate number of spacer washers19optionally can be provided on threaded bolt15on opposite sides of hoist mount18. Spacer washers19assure the right separation of side plates11and trolley wheels13to properly fit beam trolley10on beam20. This proper fit on beam20places the outer circumferential surfaces21of trolley wheels13on upper web surfaces22of beam20so that wheels13engage and longitudinally ride along beam20and transfer the load's weight to beam20via beam trolley10. End nuts16are securely tightened on threaded bolt16to secure these components together when they have been properly fitted.

The contemporary beam trolleys such as those described above do not have a suitable operator-controlled means for fixedly securing them to the load bearing beams. This can create unsafe lifting of loads by the trolley and hazardous stowage of an unused, unsecured trolley under unstable ambient conditions, such as on those encountered on a ship underway at sea.

Thus, in accordance with this inventive concept, a need has been recognized in the state of the art for an operator actuated means to secure a beam trolley to a load bearing beam to prevent unwanted travel of the trolley along the beam.

SUMMARY OF THE INVENTION

The present invention provides a cam actuated brake mechanism that allows an operator to selectively secure a beam trolley on a supporting beam. The brake mechanism has a body member on the beam trolley adjacent to the beam. The body member has a recess and axially aligned bores and a rotatable lateral pin extends through the aligned bores. The lateral pin has a rotatable elongate cam portion extending across the recess, and a brake pad is in the recess adjacent to the beam and abutting the cam portion. A handle is connected to the lateral pin for rotating the pin and the cam portion to displace the brake pad against the beam. The brake pad frictionally secures the beam trolley on the beam and locks the rotatable cam in place. Rounded end portions on opposite ends of the lateral pin and sleeve-like bushings between the axially aligned bores and rounded end portions permit rotation of the cam portion by the handle. A pair of coiled springs in the recess urges the brake pad away from the body member upward and outward and the springs have securing means at opposite ends for coupling the springs to the brake pad and body member at the bottom of the recess. A load bearing hoist mount is integrally formed with the body member for bearing a load and is mounted midway on a laterally extending threaded bolt of the beam trolley. The body member has a transverse bore having the bolt extending through it, and the transverse bore, hoist mount, cam portion, and brake pad are in an essentially in-line arrangement in the brake mechanism to reduce generation of destabilizing torques.

An object of the invention is to provide a cam actuated brake mechanism that allows an operator to selectively secure a beam trolley on a supporting beam.

Another object of the invention is to provide a cam actuated brake mechanism to secure a loaded or unloaded beam trolley along the length of a supporting I- or H-beam.

Another object of the invention is to provide a brake mechanism capable of accommodating commercially available beam trolleys to provide for improved safety and handling.

Another object of the invention is to provide a brake mechanism for modifying a number of commercially available beam trolleys to improve safety and handling without compromising their inherent load-bearing capabilities.

These and other objects of the invention will become more readily apparent from the ensuing specification when taken in conjunction with the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring toFIGS. 3 and 4, in conjunction withFIGS. 1 and 2, a cam actuated brake mechanism30is mounted on a beam trolley10to engage an I or H beam20to selectively secure a loaded or unloaded beam trolley10on beam20. While the beam20as illustrated and described herein is an I or H beam, it should be understood that the present invention will operate on any suitable beam having a flange on which a typical trolley10can operate.

Brake mechanism30has an essentially cylindrically-shaped steel body member32having a transverse bore33and an integral load bearing hoist mount34for bearing a load35. Hoist mount34is mounted midway on laterally extending threaded bolt15of beam trolley10, which extends through transverse bore33. Some or all of spacer washers19of beam trolley10may also have to be removed when hoist mount34of brake mechanism30is included to keep the proper spacing of components of beam trolley10on beam20. This feature of brake mechanism30of the invention allows the accommodation and modification of a number of commercially available beam trolleys and gives these modified devices improved safety and handling without compromising their inherent capabilities.

Referring also toFIG. 5, body member32is machined to form an upwardly facing exposed recess36to receive a semi-rigid brake pad38. Brake pad38can be fabricated from a wide variety of known tough, wear-resistant composite materials and could be provided with a rigid backing component if desired to assure braking of brake mechanism30and any attached load on beam20. Brake pad38is supported from the bottom40of the recess36by a pair of coiled springs42or other resilient means that urges pad38away from body member32and upward and outward from recess36adjacent to and preferably abutting beam20. Springs42can be secured by appropriate mechanical or adhesive securing means43known in the art to brake pad38and body member32at bottom40. Springs42help retain brake pad38in recess36and maintain the alignment of brake pad38with beam10to ensure that brake pad38contacts flat against beam10and to prevent the possibility of the pad's sticking in any one position during actuation of brake mechanism30by handle66.

Body member32has aligned bores44and46in communication with recess36to receive a lateral pin48. Lateral pin48is preferably machined from a piece of steel or other tough stock to have axially aligned cylindrical end portions50and52that are concentric with a central axis54of lateral pin48. Sleeve-like bushings56and58are placed respectively between bores44and46and end portions50and52to permit selective bidirectional rotation of lateral pin48. Lateral pin48is also machined with an elongate cam portion60that has a cross-sectional shape that is not concentric with central axis54and extends between end portions50and52in recess36. Cam portion60is adjacent to and abuts brake pad38in recess36. When cam portion60of pin48is rotated, cam portion60moves eccentrically to overcome the biasing force of springs42and displaces, or lifts, brake pad38away from bottom40of recess36to engage lower surface64of beam20, as shown inFIG. 3. During assembly of brake mechanism30, the cross-sectional dimensions of cam portion60permit its insertion into recess36through either of bores44or46.

A rigid handle66is securely connected to pin48by a tightened threaded bolt68inserted through handle66in line with central axis54. Rotation of handle66by an operator to the normal operating position shown inFIGS. 3 and 7rotates cam portion60to displace brake pad38sufficiently to engage lower surface64of beam20. In the normal operating position handle66is slightly off-center from vertical and the force of gravity on handle66causes just enough pressure to be exerted by cam portion60to maintain light contact between brake pad38and lower surface64of beam20. This contact is with sufficient frictional force to hold cam portion60in place on brake pad38and create enough drag to restrict an unloaded beam trolley10from undesired motion along beam20by the influences of light ambient wind or roll of a ship underway, for example.

However, when a load must be positively secured under more intense ambient conditions and the trolley needs to be prevented from rolling in either direction, the operator forcefully rotates handle66to the locked position shown inFIGS. 6 and 8. Cam portion60is rotated to displace brake pad38sufficiently to create a large amount of brake friction between brake pad38and lower surface64. This large amount of frictional force securely engages and locks brake pad38onto beam20and prevents a loaded beam trolley10from moving. To reset brake mechanism30from the locked position an operator simply swings rigid handle66to the normal or rest position. In either the normal or locked position, cam portion60is subjected to sufficient friction from brake pad38and brake pad38is made from a suitable known material as to be “self-locking”, or hold it in place and maintain brake force. Therefore, cam portion60is unable to counter-rotate to disengage free without additional counter-rotational force being applied to the handle by an operator.

Cam actuated brake mechanism30provides positive locking of a beam trolley10to allow safe lifting of loads under unstable conditions such as while a ship is proceeding underway at sea. Transverse bore33, hoist mount34, cam portion60, and brake pad38are disposed in an essentially vertical in-line arrangement along the length of brake mechanism30to reduce or eliminate the generation of destabilizing torques during actuation of brake mechanism30. Thus, the reliable engagement of beam20by brake mechanism30is not destabilized or otherwise compromised. Cam actuated brake mechanism30can be adapted to a number of commercially available beam trolleys to assure a higher level of safety and reliability.

It should be readily understood that many modifications and variations of the present invention are possible within the purview of the claimed invention. It is to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.