US3826353A

US3826353A - Conveyors

Info

Publication number: US3826353A
Application number: US00278166A
Authority: US
Inventors: C Greasley
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-08-04
Filing date: 1972-08-04
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30

Abstract

A conveyor includes a first elongated support which is movably coupled to a support structure, and a second elongated support which is supported by the first support. A conveyor belt, engaged with the first support, the second support, and a motor, tends to extend or retract the second support with respect to the first support depending on the sense of rotation imparted to the belt by the motor. However, brake means connected between the first and second supports continuously create a frictional force which prevents relative motion between the first and second supports due to the action of the free running belt. The second support includes means for directly trapping the moving belt, thereby causing the belt to apply a force between the first and second supports which overcomes the frictional force provided by the brake means and creates relative motion between the first and second supports.

Description

United States Patent [191 Greasley [111 3,826,353 [451 Jul 30, 1974 CONVEYORS [76] Inventor: Cecil Henry Greasley, 5 18 Chester Rd., Woodford, England 22 Filed: Aug. 4, 1972 211 Appl. No.: 278,166

Primary Examiner-Richard A. Schacher Assistant Examiner-James W. Miller Attorney, Agent, or F irmAlan H. LevinejBreitenfeld & Levine [5 7] ABSTRACT A conveyor includes a first elongated support which is movably coupled to a support structure, and a second elongated support which is supported by the first support. A conveyor belt, engaged with the first support, the second support, and a motor, tends to extend or retract the second support with respect to the first support depending on the sense of rotation imparted to the belt by the motor. However, brake means connected between the first and second supports continuously create a frictional force which prevents relative motion between the first and second supports due to the action of the free running belt. The second support includes means for directly trapping the moving belt, thereby causing the belt to apply a force between the first and second supports which overcomes the frictional-force provided by the brake means and c-reates relative motion between the first and second supports.

7 Claims, 7 Drawing Figures l CONVEYORS This invention relates to conveyors.

According to the invention a conveyor comprises a support structure, a first elongated support, a second elongated support, an endless conveyor belt movable on rollers carried by the first and second supports, means for driving the belt in either of two opposed senses, said belt being disposed so that when driven in one or other sense the belt urges said second support towards an extended or retracted position respectively in relation to the first support whilst movement of the second support is prevented by brake means, and means operable to permit the second support to extend or retract in relation to the first support.

The operable means mayv comprise means for increasing the energy transferred from the belt to the second support to overcome the brake means.

The support structure may comprise a frame or chassis to which is pivoted a further elongated support to which is pivoted the first elongated support.

The first elongated support may be pivoted to the support structure.

The invention may be performed in various ways and two specific embodiments will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of a first extensible conveyor; Y

FIG. 2 is part of FIG. 1 on an enlarged scale;

FIG. 3 is a side view of a control mechanism in a first position;

FIG. 4 is a side view of the controlmechanism in a neutral or datum position;

FIG. 5 is a side view of the control mechanism in a third position;

FIG. 6 is a section on the line 6-6 of FIG. 2 with part omitted; and

FIG. 7 is a diagrammatic view similar to FIG. 1 of an.- other conveyor.

Referring to FIGS. 1 to 6, the conveyor comprises a supporting platform or chassis 10 generally rectangular in plan constructed for example of angle girders with transverse braces. The chassis 10 is supported on spaced pairs of castor wheels ll for movement over a support surface 9 such as the floor of a warehouse or loading bay.

Two brackets 12 extend upwardly at the corners at one end of the chassis and one end of a rigid beam assembly l3 is'pivoted to the brackets for movement about a horizontal axis under the control of a hydraulic ram 14. The ram 14 comprises a cylinder 15, pivoted at one end to a transverse member (not shown) at the mid-point thereof, and a piston 16 pivoted at 17 centrally between two laterally spaced longitudinal beams 18 (only one shown) of the assembly 13, the beams 18 being connected by rigid transverse members.

A further rigid boom or beam assembly 19 comprises two laterally spaced beams 20 with connecting transverse members and is pivoted at one end about horizontal axis 21 to the forward end of assembly 13.

A hydraulic ram 24 pivoted to assemblies 13 and 19 is provided to pivot assembly 19 about axis 21.

Another rigid boom or beam assembly 22 comprising two laterally spaced longitudinal beams 23 with connecting transverse members is disposed beneath boom 19 for forward and rearward, or extension or retrac- 2 tion, movement relative thereto as indicated by the arrows and described later.

The beam assemblies support a number of longitudinally spaced lateral rollers 25 (some omitted for clarity) for supporting the upper and lower runs of an endless conveyor belt 26 of suitable material such as reinforced rubber. The rollers have shafts 27 mounted in bearings 28 for easy running.

The belt 26 is driven by an electric motor 30 under the control of forward, stop and reverse switch buttons provided in control assembly 31 mounted on one side of the forward end of extensible boom 22 and control assembly 31A mounted on structure 13 near the other end of the machine. The belt 26 passes over roller 32 at the rear end of assembly 19, the roller 32 being so located in relation to pivot axis 21 that as assembly 19 moves up and down in relation to assembly 13 the tension in the belt remains substantially unaltered. The belt 26 passes over roller 33 near the forward end of assembly 19 and over roller 34 at the rear end of boom 22 and over roller 35 at the forward end .of boom 22.

' Hydraulic pump 36 may be manually operated by handle 37 to raise and lower the assembly l3 through ram 14 and hydraulic pump 38 may be manually operated by handle 39 to pivot assembly 19 through ram 24. In a modification the pumps are operated electrically under the control of suitable switches. Also it is possible to use a single pump with a changeover valve operable to direct the fluid to the appropriate ram as desired. Vertically adjustable castor wheels 40 are carried by the forward end of assembly 19 to support the assembly if desired on a surface such as the body of a lorry, or the floor of a container into which boom 22 extends.

When the belt is running in a forward direction, the tension in the belt urges the boom 22 towards the extended condition, but movement of the boom 22 is prevented by brake assembly 41. When the belt is running in the reverse direction, the tension in the belt urges the boom 22 towards the retracted position. Brake assembly 41 comprises a vertical-plate 42, supported from the assembly 19 and extending longitudinally beneath the assembly, and brake pads 43, 44 engageable with opposite faces of. plate 42. The pads are carried by boom 22, and pad 44 is urged towards plate 42 by spring 45. The pad 43 is adjustable laterally by bolts 46, and part-threaded bolt 47 extends through'boss 47A and is engaged by nut 47B enabling adjustment of the length of spring and thus of the force with which pad 44 engages plate 42. a

At the forward end of boom 22 is boom extension and retraction control mechanism 50. In the neutral position (FIG. 4) belt 26 is spaced from a rod 57 fixed in the boom 22 and from-a manually operable handle 52 having a cross-member 53. The position of roller 35 may be adjusted forwards or rearwards by adjustment of support bracket 54 on threaded rod 55 and is held in position by nuts 56.

' When it is desired to extend boom 22, the handle is pivoted forwardly as in FIG. 3 to trap the belt 26 between the cross-member 53 and bar 57 thus arresting movement of the belt. The tension in the belt then overcomes the action of the brake and causes the boom 22 to extend with belt running forward" and when the desired extension has been reached the handle is returned to the neutral position.

When it is desired to retract the boom 22, the handle is pivoted rearwardly with belt running in reverse as in FIG. 5 and is returned to the neutral position when the desired retraction has been achieved.

This provides easy and smooth extension and retraction under the control of the operator, and may be carried out at all positions of

assemblies

13 and 19. The boom 22 moves on peg 22A and roller 22B carried by boom 19. The control buttons for the belt motor may be located at other positions, for example near the forward end of assembly 19. Also only one, or more than two, sets of control buttons could be provided.

The chassis is provided with balance weight 60 and may have means for locking the chassis to the floor 9, such as feet 6l'carried on threaded rods extending throughthreaded brackets on the chassis.

The machine may include a power operated crab, as shown, including power driven wheels 70, mounted on a framework 71 supporting an electric motor and worm reduction gear for driving wheels 70.

The framework'7l is pivotted to the chassis 10 by horizontal pivot 72. When the power crab is in operation handle. 73 is screwed down forwards so that the wheels 70 come into contact with the floor 9 and raise castors ll clear of the floor. The loader or conveyor can then be propelled forwards and rearwards' along the floor by a fail safe pushfbutton control associated with the crab motor.

Whenever it is required to move the apparatus manually, handle 73 is operated so that wheels 70 pivot the frame 71 upwards about pivot 72 and thus raise the driving wheels 70 clear of the floor. The chassis then reverts to support on castors 11.

The boom 22 may extend below the level of the chassis, or assemblies l3, 19, 22 may be in line. Other positions of adjustment are of course possible.

In a modified arrangement shown in FIG. 7, there are two separate

endless belts

26 and 26A each with separate drive motors and the

assemblies

13 and 19 are not pivoted together but to a support 76.

It will be appreciated that the assembly 19 could be omitted and the boom 22 secured beneath the assembly 13, or vice versa.

The chassis could be fixed to the supporting surface instead of being on wheels.

Also, the structure 13 need not be pivoted to the chassis but could simply extend therefrom, and in this case the ram 14 and associated parts would be omitted.

The apparatus may be provided with mechanism by which it may be, towed; for example the chassis may be provided with a towbar attached to an Ackerman steering device which can swing about a vertical axis.

In a modified arrangement, instead of trapping the belt so as to overcome the brake, the brake is released somewhat to allow extension or retraction of the boom 22 and then re-engaged to arrest the boom in the desired position. In this case, it may be necessary to operate the brake with power assistance, for example by way of an electric or electromagnetic device.

I claim:

1. A conveyor, comprising: a support structure; a first elongated support coupled to the support structure; a second elongated support movably coupled to the first support; an endless conveyor belt movable on rollers carried by the first and second supports, means for driving the belt in either of two opposed senses, said belt being disposed so that when driven in one or other sense the belt urgessaid second support towards an extended or retracted position, respectively, in relation to the first support; brake means for providing a continuous frictional engagement between the first and second support to resist movement of the second support with respect to the first support by means of the free running belt;.and means for directly trapping the belt to overcome the friction force of said brake means, thereby causing the belt, depending on its sense of movement, to extend or retract the second support with respect to the first support, said belt-trapping means comprising a handle operable to trap the belt between the handle and a member fixed in relation to the second support.

5. A conveyor as claimed in claim 1, in which the support structure includes a main support and a further elongated support pivoted to the main support and to the first support and carrying rollers engageable with the belt, and means for effecting pivotal movement of the further elongated support.

6. A conveyor as claimed in claim 5, in which the belt drive means is mounted on the further elongated support.

7. A conveyor as claimed in claim 1, in which the support structure is mounted on wheels.

Claims

1. A conveyor, comprising: a support structure; a first elongated support coupled to the support structure; a second elongated support movably coupled to the first support; an endless conveyor belt movable on rollers carried by the first and second supports; means for driving the belt in either of two opposed senses, said belt being disposed so that when driven in one or other sense the belt urges said second support towards an extended or retracted position, respectively, in relation to the first support; brake means for providing a continuous frictional engagement between the first and second support to resist movement of the second support with respect to the first support by means of the free running belt; and means for directly trapping the belt to overcome the friction force of said brake means, thereby causing the belt, depending on its sense of movement, to extend or retract the second support with respect to the first support, said belt-trapping means comprising a handle operable to trap the belt between the handle and a member fixed in relation to the second support.

2. A conveyor as claimed in cLaim 1, in which the belt trapping means is mounted at a forward location on the second support.

3. A conveyor as claimed in claim 1, in which the brake means comprises brake pads carried by the second support engaged with an elongated brake plate carried by the first support.

4. A conveyor as claimed in claim 1, including hydraulic means for pivoting the first support in relation to the support structure.