GB2204294A - Roller conveyor with adjustable roller pitch - Google Patents

Description

A 1 k C) 2 0 J1 ROLLER CONVEYOR

FIELD OF THE INVENTION

The present invention relates to a roller conveyor which is of a continuous driving type having driving rollers pressed against the outer peripheries of free rollers and yet allows the roller pitch to be changed as desired.

BACKGROUND OF THE INVENTION

This type of roller conveyor is known and is disclosed for example in USP 4,488,639. This conventional roller conveyor includes a number of free rollers capable of only free rotation disposed on a main frame to define a transfer path, and a support frame associated with the main frame.

The support frame is provided with pins extending along the roller axes, each of said pins being provided with a wheel and a sprocket, said wheel and sprocket being rotatable integrally and said wheel being simultaneously contactable with a pair of adjacent free rollers. A driving chain guided along said main frame is engaged with the sprockets.

According to this conventional type, the wheels are rotated by the driving chain through the sprockets, and the rotation of each wheel is transmitted to the pair of free rollers contacted therewith, so that objects to be transferred are transferred on the transfer path by the rotation of the free rollers groups.

According to such conventional type, since the free rollers are stationary with respect to the main frame, the roller pitch cannot be changed according to the shape and length of objects to be transferred and the conveyor system becomes expensive when the roller pitch is reduced so as to smoothly transfer objects of minimum shape and length.

Similarly, since the support frames are stationary, a large number of them are required.

DISCLOSURE OF THE INVENTION

An object of the invention is to provide a roller conveyor which makes it possible to change the roller pitch as desired and also change the position of the driving rollers accordingly.

To achieve this object, a roller conveyor according to the invention comprises:

a main frame, support frame means attached to said main frame so that its position lengthwise of said main frame can be changed as desired, free rollers rotatably attached to the top of said support frame means for,transferring objects to be transferred, support shafts disposed in the lower region of said support frame means and extending along the axes of said free rollers, said support shafts being vertically swingably attached to said support frame means, a transmission roller and a driven wheel which are supported on each said support shaft and rotatable as a unit, upward movement imparting means attached to said support frame means and operatively connected to said support shafts to move the latter upward, thereby pressing said transmission rollers against the lower regions of the outer peripheries of said free rollers, driving means associated with said main frame and operatively connected to said driven wheels to drive the latter.

According to this arrangement, the transmission rollers are rotated by the driving means through the driven wheels, and in this state, the transmission rollers are moved upward by the upward movement imparting means through the support shafts, whereby the free rollers against which the transmission rollers are pressed are forcibly driven for transferring objects. Further, by changing the attaching position of the support frame means with respect to the main frame, the roller pitch can be changed as desired; thus, the number of units consisting of the free rollers and transmission rollers can be reduced in accordance with the shape and length of objects to thereby save the overall cost and make the driving device compact.

Moreover, since the positions of the units can be changed as desired, when a diverging device or converging device is installed on the side of the main frame somewhere in the conveyor line, the adjustment of the attaching position of such device is facilitated. Since there is no part interposed between adjacent units, i.e., adjacent free rollers, a stopper device for objects to be transferred or a diverging conveyor can be incorporated as desired. Further, since the free rollers and the transmission rollers are unitized by the support frame means, the accuracy of arrangement of these rollers is secured.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a sectional side_view of a first embodiment of a roller conveyor according to the present invention; Fig. 2 is a sectional front view of the roller conveyor shown in Fig. 1; Fig. 3 is a plan view of a portion of the roller conveyor shown in Fig. 2; Fig., 4 is a perspective view of a portion of a support frame used in the roller conveyor shown in Figs. 1 through 3; Fig. 5 is a perspective view of another portion of said support frame; -T Fig. 6 is a diagrammatic side view of the entire roller conveyor shown in Figs. 1 through 5; Fig. 7 is a fragmentary diagrammatic side view showing that the roller pitch of the roller conveyor shown in Fig. 6 has been changed; Fig. 8 is a sectional side view of a second embodiment of a roller conveyor; Fig. 9 is a sectional front view of the roller conveyor shown in Fig. 8; Fig. 10 is a sectional front view showing that a transmission roller in the roller conveyor shown in Fig. 9 has been separated from the free roller; Fig. 11 is a diagrammatic side view of the roller conveyor shown in Figs. 8 through 10; Fig. 12 is a sectional side view of a third embodiment of a roller conveyor according to the invention; Fig. 13 is a sectional front view of the roller conveyor shown in Fig. 12; Fig. 14 is a perspective view of a cover used in the roller conveyor shown in Figs. 12 and 13; Fig. 15 is a diagrammatic side view of the entire roller conveyor shown in Figs. 12 through 14; Fig. 16 is a sectional diagrammatic side view showing that the roller pitch of the roller conveyor shown in Fig.

has been changed; Fig. 17 is a sectional side view of a fourth embodiment of a roller conveyor according to the invention; Fig. 18 is a sectional front view of the roller conveyor shown In Fig. 17; Fig. 19 is a view showing the other support frame used in the roller conveyor shown in Figs. 17 and 18; Fig. 20 is a sectional side view of a fifth embodiment of a roller conveyor of the invention; Fig. 21 is a sectional front view of the roller conveyor shown in Fig. 20; Fig. 22 is an enlarged sectional detailed view of the guide frame portion shown in Fig. 20; Figs. 23A and 23B are enlarged perspective views, showing an arrangement around the support frame shown in Fig. 20;.

Fig. 24 is a view showing an example of an arrangement around the support frame; Fig. 25 is a view showing another example of an arrangement around the support frame; Fig. 26 is a diagrammatic side view of the roller conveyor shown in Figs. 21 through 25 in its entirety; Fig. 27 is a diagrammatic side view wherein part of the roller conveyor shown in Fig. 26 serves as a non-driven region; Fig. 28 is a diagrammatic side view showing the state 7 in which the roller pitch of the roller conveyor shown in Figs. 26 and 27 is changed; Fig. 29 is a sectional view showing another example of a guide frame; Fig. 30 is a sectional side view of a transmission unit in Fig. 21; Fig. 31 is a view showing one side of an arrangement around an annular boss portion in Figs. 21 and 30; 1 Fig. 32 is a view showing the other side of an arrangement around the annular boss portion of Fig. 31; FIg. 33 is a sectional view for explaining the action of vanes and vent holes in Figs. 30 through 32; Fig. 34 is a sectional side view of a sixth embodiment of a roller conveyor of the invention; Fig. 35 is a sectional front view of the roller conveyor shown in Fig. 34; Fig. 36 is a diagrammatic side view for explaining a first operating state of the roller conveyor shown in Figs.

34 and 35; Fig. 37 is a diagrammatic side view for a second operating state of the roller conveyor shown in Figs. 34 and 35; and Fig. 38 is a sectional front view showing another example of arrangement of a transmission unit and a brake unit in the roller conveyor shown in Figs. 34 through 37.

DESCRIPTION OF THE EMBODIMENTS

A first embodiment of the invention will now be described with reference to Figs. 1 through 7.

The numeral I denotes a main frame made of metal and having a U-shaped cross-section. Said main frame comprising a pair of lateral frames 1A and 1B and a base frame IC connecting the lower ends of said lateral frames 1A and 1B.

The opposed inner surfaces of the lateral frames 1A and 1B 4e are fromed with L-shaped guides 2A and 2B.

upper regions of the lateral frames 1A and 1B are formed with grooves 4A and 4B which allow the sliding of nuts 3A and 3B.

In one lateral frame 1A, the lower inner'surface region thereof has a pair of upper and lower guide rails 7 and 8 associated therewith through attachments 5 and 6, said guide rails extending lengthwise of the frame.

The attachments 5 and 6 are integral with the lateral frame 1A. Therefore, the guide rails 7 and 8 can be easily disposed at the predetermined positions. The main frame I and the attachments 5 and 6 are integrally formed of aluminum; thus, a frame construction which has sufficient mechanical strength and rigidity can be expected. Despite the fact that the frame construction can be made small in size, heavy objects can be transferred.

The inner surfaces of the lateral frames 1A and 1B are provided with support frames 9A and 9B of resin which are fitted at their lower ends in the L-shaped guides 2A and 2B so that their positions can be changed lengthwise of the frame (they are slidable). These support frames 9A and 9B are fixed in position by passing bolts 10A and 10B through the upper regions thereof and threadedly engaging them with said nuts 3A and 3B so that their positions can be changed.

The upper portions of the support frames 9A and 9B are formed with locking portions 11A and 11B. The opposite ends of roller shaft 12 are locked in said locking portions 11A and 11B, whereby a free roller 13 of resin is freely rotatably installed between the support frames 9A and 9B.

One support frame 9A is in the form of a case comprising a base plate 14 formed with the lower end to be fitted in said guide portion 2A and said locking portions IIA, a pair of cover plates 15 extending inwardly from the lower half of the inner surface of the base plate 14, and a connecting plate 16 disposed between the lower ends of the cover plates 15. The other support frame 9A is in the form of a rectangular plate.

Vertically swingably attached to one support frame 9A is a support shaft 18 extending along the roller axis 17.

That is, the inner surface of the lower end of the base plate 14 is formed with a cylindrical bearing 19, and a ball 18a formed on one end of said support shaft 18 is fitted in said bearing 19, so that the support shaft 18 is vertically swingable around said ball 18a. An L-shaped plate 35 is attached between the lateral ends of the cover plates 15, and the other end of said support shaft 18 is fitted in a vertically extending elongated opening 36 formed in the vertical plate portion of said L-shaped plate 35.

The support shaft 18 has s sprocket 20, which is an example of a driven wheel, rotatably attached thereto. The boss of the sprocket 20 has a transmission roller 21 fitted thereon. The sprocket 20 and transmission roller 21 are rotatable as a unit. The transmission roller 21 comprises an inner wheel 21a of metal or resin fitted on the boss of the sprocket 20 through a friction transmission section (slip allowing section) 22, and an outer wheel 21b of urethane rubber fitted on said inner wheel 21a, the outer wheel 21b being contacted with the lower region of the outer periphery of the free roller 23. That is, a coil spring 37, which is an example of an upward movement imparting device which effects pressure contact, is interposed between the lower surface of the other end of the support shaft 18 and the bottom plate portion of the L-shaped plate 35. The parts denoted by the reference characters 9A, 9B through 22, through 37 described above form a transmission unit 40, and a number of such transmission units 40 are disposed lengthwise of the main frame 1; thus, a group of free rollers 13 define a transfer path 23. A chain 24 which is a common drive section operatively connected to the sprockets is supported and guided by the guide rails 7 and 8. The chain 24 is installed under tension between a driving sprocket 25 and driven sprockets 26 through guide sprockets 27, said driving sprocket 25 being operatively connected to a motor 29. The numeral 30 denotes objects to be transferred.

Since the attachments 5 and 6 supporting the guide rails 7 and 8 are integral with the main frame 1, as described above, the accuracy of the installation of guide rails 7 and a is improved. Thus, the chain 24 can be accurately engaged with the sprockets 20 to provide a satisfactory driving state.

However, according to the conventional type of USP 4,488,639, the guide rails or the attachments supporting the guide rails are not integral with the main frame but held up by the main frame by mean,-, of bolts. Therefore, according to this conventional structure, such operational effects of the present invention as above-mentioned can not be expected at all.

The transfer operation will now be described.

Figs. 1 and 6 show the operating state with the roller pitch P adjusted to a minimum. The chain 24 is constantly driven by the motor 29, so that all the sprockets 20 engaging the chain 24 are rotating around the axes of the support shafts 18. Further, each transmission roller 21 is contacted with the lower region of the outer periphery of the free roller 13 by the resilient force of the coil spring 37; thus, the group of free rollers 13 are forced to rotate, so that objects 30 can be transferred along the transfer path 23. When an object 30 is stopped by a stopper device (not shown), since the friction transfer force of the free roller 13 on the object 30 is greater than the friction force of the friction transfer section 22, the boss of the sprocket 20 slidingly rotates with respect to the inner wheel 21a. Thus, while the sprocket 20 i s constantly rotating, the rotation of the free roller 13 is stopped, so that the object 30 can be stored without causing a sliding contact state on the lower side.

When the object 30 is a long-sized one as shown in Fig.

7, the roller pitch P can be increased to reduce the number of transmission units 40 consisting of free rollers 13 and transmission rollers 21. This can be attained by loosening the bolts 10A and IOB, moving the support frames SA and 9B toward the transfer path 23 along the guides 2A and 2B, and tightening the bolts IOA and 10B with respect to the nuts 3A and 3B which have been moved integrally with the support frames SA and 9B and bolts IOA and IOB. During this, excess free rollers 12 and support frames SA and 9B are removed.

Figs. 8 through 11 show a second embodiment of the 13 invention. In the second embodiment, rotatably attached to the two cover plates 15 at a position closer to the base plate 14 is a shaft 38 extending in the direction of transfer at right angles with the roller axis 17. A cylinder device 39, which is another example of an upward movement imparting device, is-installed between one end of the support shaft 18 and the connecting plate 16. In this case, the cylinder device 39 has a main body 39a fixed to the connecting plate 16 and a rod 39b contacted at its front end with the support shaft 38.

According to this second embodiment, the cylinder device 39 upwardly moves the transmission roller 21 together with the support shaft 18 and presses the transmission roller 21 against the free roller 13, whereby a group of free rollers 13 are forcibly rotated, as in a driving region 31 shown in Fig. 11, to transfer objects 31 along the transfer path 23. Further, the cylinder device 39 is reversely operated to lower the transmission roller 21 until the latter is separated from the free roller 13, whereby transmission from the transmission roller 21 to the free roller 13 is interrupted. Thus, the rotation of the group of free rollers 13 is stopped, as in a non-driving region 32 shown in Fig. 11, to store the object 30 on the transfer path 23.

At this time, in the driving region 31, the object 30 is sensed by a sensing lever or phototube device and the free rollers 13 located forwardly of the object 30 in the direction of transfer are successively rotated, while the free rollers 13 passed over by the object 30 are successively stopped; by so controlling, the object 30 can be progrssively displaced in the direction of transfer. In a particular location, a non-driving region 32 can be defined by a control signal so as to store the object 30.

Further, the driving region 31 can be automatically controlled to be converted into a non-driving region 32 when the subsequent object 30 approaches the preceding object 30; thus, continuous storage can be effected without collision.

Figs. 12 through 16 shows a third embodiment of the invention.

The lateral frames 1A and 1B are obtained by extrusion of aluminum. At this time, simultaneously with the formation of the guides 2A and 2B and grooves 4A and 4B, the inner side of the lower attachment 6 is formed with a top opened holding groove 41 extending throughout the region lengthwise of the transfer path 23, and a locking piece 42 inwardly projecting above the upper attachment 5 is formed throughout the region lengthwise of the transfer path 23. A cover 43 which covers the top and inner side of the path of transfer of the chain 24 is provided between adjacent transmission units 40. The cover 43 is an aluminum extruded article of substantially L-shaped cross section, and is cut into required lengths in use. The lower end of the vertical plate portion 44 of the cover 43 forms an insert portion 44a to be inserted from above into the holding groove 41, while the front end of the transverse plate portion 45 thereof forms a locking portion 45a to be locked from below to the locking piece 42. The cover 43 can be attached between transmission units 40 by inserting the insert portion 44a from above into the holding groove 41 and locking the locking portion 45a to the lower locking piece 42 by utilizing the elasticity of the cover 43.

During transfer operation, foreign substances from the object 30 will drop into a space between adjacent free rollers 13. Those foreign substances which fall onto the free roller 13 will-slide down the free roller 13 to fall into a space between adjacent free rollers 13. Therefor.e,' the transmission unit 40 consisting of the spiocket 20 and transmission roller 21, and the chain 24 located therebelow are protected from the foreign substances by the free rollers 13 and cover plate 15. All the foreign substances will drop from a space between free rollers 13, as described above, but since the chain 25 located between and below the free rollers 13 is covered with the lateral frame 1A and cover 43, they will never drop onto such parts.

Further, the provision of the covers prevents an operator who performs conveyor operating from accidentally putting his hand into the operating section of the chain 24.

Thus, safety is secured.

When a long-sized object shown in Fig. 16 is handled as an object 30 to be transferred, the pitch P is increased and long-sized covers 43 corresponding to the changed pitch P are utilized.

In the above embodiment, the covers 43 have been of the type adapted to be removed from the lateral frames 1A and 1B. However, they may be of the type adapted to be removed from the transmission units 40.

Figs. 17 through 19 shows a fourth embodiment of the invention.

The base plate 14 of one support frame 9A is formed with locking holes 53a and 53b. The other support frame 9B Is in the form of a rectangular plate having a pair of upper and lower attaching holes 54B for receiving a bolt 10B.

Opposite sides of the support frame 9B with the attaching holes 54B interposed therebetween are formed with locking grooves 55a and 55b which are opened at end surfaces of the support frame 9B., The distances L, and L2 from the bottoms of the locking grooves 55a and 55b to the attaching holes 54B are made equal to the distances L, and L2 from the attaching hole 54A, formed in one support frame 9A to receive the bolt 10A, to the locking holes 53a and 53b. The free roller 13 has its roller shaft 12 inserted at one end thereof in either of the locking holes 53a and 53b and at the other end thereof in either of the locking grooves 55a and 55b from above and supported on the bottom of the groove.

The width dimensions of the locking grooves 55a and 55b are such that the innermost width W, (arc diameter) is somewhat greater than the diameter D of the roller shaft 12 and the inlet width W2 is further greater than said diameter D, and projections 56a and 56b are formed between these regions, the width W3 between these projections 56a and 56b being somewhat smaller than said diameter: 42>WI>D>WS.

Thus, the shaft 12 dropped Into the locking groove 55a or 55b passes over the projections 56a or 56b by depressing them, so that during normal operation the projections 56a or 56b serve as stoppers which prevent upward withdrawal.

When free rollers of different diameter is used because of changes of the transfer speed or roller pitch P, the free rollers 13 now in use will be first removed. At the time, the operator raises the end of the free roller 13 associated with the support frame 9B, forcibly moving the end of the roller shaft 12 through the space between the projections 56a and 56b until it is upwardly removed from the locking groove 55a or 55b. Then the operator pulls the free roller 13 lengthwise of the latter to extract the other end of the roller shaft 12 from the locking hole 53a or 53b. And be resets the support frame 9A by turning it upside down.

Subsequently, he inserts one end of the roller shaft 12 of a new free roller 13 into the locking hole 53b or 53a and the other end into the locking groove 55b or 55a. In this manner, the free roller 13 can be easily and quickly changed.

Figs. 20 through 33 show a fifth embodiment of the invention.

The upper portions of support frames 9A and.9B for a transmission unit 40 are formed with recesses 60A and 60B whose upper and inner surfaces are opened, while the upper portions of erected elements 61A and 61B positioned at the outer sides of the support frames 9A and 9B are formed with guide surfaces 62A and 62B which are inclined outward the more the upper region is approached. The front and rear surfaces of the recesses 60A and 60B are defined by pawl bodies 63A and 63B having inward pawl portions 63a and 63b in the upper ends. The back and upper portions of the pawl bodies 63A and 63B are provided with grooves 64A and 64B whose upper surfaces and opposite lateral surfaces are opened, and following these grooves 64A and 64B, the lower portions are provided with tapping grooves 65A and 65B, so that these pawl bodies 63A and 63B are forwardly and rearwardly swung against their own elasticity.

Formed on the upper surfaces of tiie support frames 9A and 9B and forwardly and rearwardly outwardly of the grooves 64A and 64B are recessed step portions 66A and 66B. Lid members 67A and 67B fitted from above in said step portions 66A and 66B to close the upper surfaces of the recesses 60A and 60B have through-holes 68A and 68B capable of being opposed to the tapping grooves 65A and 65B. The inner ends of the lower surfaces of the lid plates 69A and 69B for insertion from above into the grooves 64A and 64B, while the outer ends of the lower surfaces thereof are formed with wedging elements 70A and 70B whose outer surfaces are inclined and which can be inserted between the pawl bodies 63A and 63B.

A free roller 13 of resin is idly rotatably installed between the support frames 9A and 9B through a roller shaft 12. More specifically, install'ed on the opposite ends of the roller shaft 12 idly rotatably fitted in the free roller 13 are bearing bodies 71A and 71B adapted to be fitted from above into the recesses 60A and 60B. The bearing bodies 71A and 71B are in the form of rectangular blocks which are centrally formed with through-holes 72A and 72B through which the roller shaft 12 is inserted, the upper end corner portions thereof being formed with locked portions 73A and 73B in the form of recesses adapted to be engageable by the pawl portions 63a and 63b. In addition, pluralities of said bearing bodies 71A and 71B with the vertical positions of their through-holes 72A and 72B changed are prepared. The attachment of the roller shaft 12 is effected by fitting the bearing bodies 71A and 71B in the recesses 60A and 60B, and the free roller 13 is rendered idly rotatably around the roller axis 17.

An L-shaped plate 35 in the support frame 9A is made from resin and is attached in position by being fitted in the free end of the cover plate 15, said L-shaped plate 35 being formed with a vertically extending recess 7.4 for controlling the vertical swing range of the support shaft 18 by getting the other end of the support shaft 18 therein.

In this embodiment, same air cylinder device 75 as the one shown in the third embodiment described above is installed on the transverse plate of the L-shaped plate 35 to serve as upward movement imparting means for pressing the transmission roller 21 against the free roller 13. The air cylinder device 75 comprises a main body 76 fixed to the transverse plate, and a rubber body (a kind of flexible body) fixed to the upper portion of said main body 76 through a fixing member 77, said rubber body 78 being adapted for vertical expansions and contraction by supplying a fluid, such as air, into and extracting it from an actuation chamber 79 formed below the rubber body 78. The rubber body 78 is capable of abutting from below against a )-X cylinder rubber support 80 attached to the other end of the support shaft 18, said cylinder rubber support 80 is integrally formed with a cap-like cover body 81 sufficiently large to completely cover the rubber body 78 from above.

Between the lateral frames 1A and 1B, a support frame is Installed to extend across a plurality of base frames 1C in the direction of the transfer path 23. This support frame 85 is in the form of a rail which has a dovetail groove 86 centrally formed in the lower surface thereof and dovetail grooves 87a and 87b centrally formed in opposite lateral surfaces thereof and a tapping groove 88 centrally formed in the upper surface thereof and tapping grooves 89a, 89b, 90a and 90b formed above and below the dovetail grooves 87a and 87b in the opposite lateral surfaces. Further, the support frame 85 is formed on its opposite lateral surfaces with upward engaging portions 91a and 91b above the tapping grooves 90a and 90b and also with downward engaging portions 92a and 92b below said tapping grooves. The support frame is fixed to the base frame 1C by a nut 93 positioned in the dovetail groove 84 and a bolt 94 and supports the L shaped plate 35 through a nut 95 positioned in the dovetail groove 87 on one side and a bolt 96.

Further, the support frame 85, as shown in Fig. 24, supports a bracket 98 having an Item presence detector 97 by engaging its engaged portion 99 with the'engaging portion 91b and then screwing a tapping screw 100 Into the tapping groove 89b. Further, as shown in Fig. 25, there can be provided lower half frame bodies 102a and 102b with engaged portions 101a and 101b engaged with the engaging portions 92a and 92b and an upper half frame body 104 engaged at its lower end with the upward engaging grooves 103a and 103b fromed on the outer ends of said lower half bodies 102a and 102b, and duct sections 106a and 106b can be formed on both sides of the support frame 85 by screwing a tapping screw 105, passed centrally through the upper half frame body 104, into the tapping groove 88. Electric wires may be installed In the duct sections 106a and 106b.

Objects 30 to be transferred are supported and transferred through wooden pallets 108. In the sprocket 20, the annular boss portion 111 having the transmission

roller 21 fitted thereon is formed with a plurality of circumferentially spaced vent holes 112 extending along the support shaft 18. The surface of the annular boss portion 111 associated with the sprocket 20 is formed with vanes 113. The vent holes are arcuate In the circumferential direction and formed at six circumferential places. The vanes 113 are formed at three circumferential places between the ends of the vent holes 112. Each vane 113 comprises a pair of vane plates 113a and 113b. These vane plates 113a and 113b are inclined so that their radial outer ends are connected together and so that the ends associated with vent holes 112 in the direction of the length of the support shaft 18 are connected together as they are contacted with the annular boss portion 111.

The upper portions of the lateral frames 1A and IB are provided with removable guide frames 120A and 120B. The guide frames 120A and 120B as well as the lateral frames 1A and IB and support frame 85 are obtained by the drawing of aluminum. These guide frames 120A and 120B are formed at their outer surfaces with outwardly opened dovetail grooves 121A and 121B and at their inner surfaces with inwardly opened locking grooves 122A and 122B in the form of dovetail grooves. The attachment of the guide frames 120A and 120B to the lateral frames 1A and IB is effected as follows: The upper regions of the outer surfaces of the lateral frames 1A and IB are formed with step portions 123A and 123B and dovetail grooves 124A and 124B which open to intermediate regions of'said step portions 123A and 123B. First, connecting plates 125A and 125B applied to the step portions 123A and 123B are fixed to the lateral frames 1A and 1B by nuts 126A and 126B positioned in the dovetail grooves 124A and 124B and bolts 127A and 127B. By nuts 128A and 128B positioned in the dovetail grooves 121A and 121B and bolts 129A and 129B, the guide frames 120A and 120B placed on the lateral frames 1A and 1B are fixed to the connecting plates 125A and 125B to complete the attachment. The guide plate of resin, for example, is removably attachable to the guide frame 120A by lengthwise inserting a locking portion 131 integral with the outer surface into said locking groove 122A. As another example, in the case where a guide plate 132 of metal, such as iron, is used, a counter-sunk bolt 135 passed through a hole 134 formed in said metal guide plate 132 is screwed into a threaded patch plate 133 positioned in the locking groove 122B. In addition, in Fig. 21, the resin guide plate 130 and the metal guide plate 132 are shown positioned on opposite sides but actually two such plates or two such plates 132 which are made of the same material suitable for the material of the pallets 108 are positioned on opposite sides.

The transfer operation based on the above construction will now be described.

Figs. 20, 21 and 26 show the state of use with the entire length of.the transfer path 23 adapted to serve as a drive region 31 by upwardly moving all the transmission rollers 21 together with the support shafts 18 by the push up forces from the air cylinder devices 75 to press them against the corresponding free rollers 13. The push-force from the air cylinder device 75 is obtained by feeding compressed air into the actuation chamber 79 to upwardly expand the rubber body 78. This push-up force is transmitted to the support shaft 18 through the cylinder rubber support 80, thus swinging the support shaft 18 upward around the pivot point on the bearing portion 19. The chain 24 is constantly driven by the motor 29 and hence all the sprockets 20 engaging the chain 24 are rotating around the respective axes of the support shafts 18. Further, the transmission roller 21 is pressed against the lower region of the outer periphery of the free roller 13, thereby forcibly rotating the group of rollers 13 to transfer the objects 30 on the transfer path 23.

During such transfer operation, an air current E is generated by the vane plates 113a of the vanes 113 being made a rotation D integral with the sprocket 20 and so on, said air current E flowing through the vent hole 112 into the cover plate section 15. Thereby, it is possible to cool the sprocket 20 and the cover plate section 15 as well as the rubber body 78. Particularly in the case where parts are made from synthetic resin, the synthetic resin tends to be degraded by heating; thus, cooling by air is effective.

Further, such location is where heat of friction is being generated and hence cooling is reguired.

In the above construction, a transmission unit 40 comprising a sprocket 20 and a transmission roller 21 has been disposed in one lateral frame IA; however, it may be disposed In the other lateral frame IB or such units may be disposed in both lateral frames 1A and 1B to drive the free roller at the opposite ends. When the transmission unit 40 is disposed in the other lateral frame IB, the direction of' rotation thereof Is relatively reversed, so that during rotation d as shown in Fig. 33, an air current e is generated by the other vane plate 113b.

During operat ion, if foreign particles, such as wood chips, fall from an object 30 to be transferred or a pallent 108, they fall onto a free roller 13 or between adjacent free rollers 13. The foreign particles falling onto a free roller 13 slip down along the free roller 13 to pass between adjacent free rollers 13, with some of said foreign particles entering the cover plate section 15. The foreign particles entering the cover plate section 15 are stopped by the cover body 81 and thereby prevented from falling onto the rubber body 78, which is thus protected from foreign materials.

In such transfer state, the bearing bodies 71A and 71B with the roller shafts 12 insertable into the through-holes 72A and 72B are fitted from immediately above into the recesses 60A and 60B of the support frames 9A and 9B.

During this fitting, the outer surfaces of the bearing bodies 71A and 71B act on the pawl portions 63a and 63b to force them apart from each other against their elasticity,' and thereafter the elastic restoring force causes the pawl portions 63a and 63b to engage the locked portions 73A and 73B, whereby the bearing bodies 71A and 71B are prevented from slipping off. The upper portions of the bearing bodies 71A and 71B are closed by the lid members 67A and 67B, at which time the push-in elements 69A and 69B are pushed into the grooves 64A and 64B while the lid members 67A and 67B are fitted in the step portions 66A and 66B. And the tapping screws 141A and 141B passed through the through holes 68A and 68B are screwed into the tapping grooves 65A and 65B, whereby the lid members 67A and 67B are.fixed in position. In that the push-in elements 69A and 69B are pushed into the grooves 64A and 64B as described above, outward deformation of the pawl bodies 63A and 63B is prevented and the engagement by the pawl portions 63a and 63b is firmly maintained.

In the case where the transfer manner described above is changed by changing the roller pitch P or using free rollers 13 of different diameter to change the transfer speed, first, the removal of the free rollers 13 now in use is effected. That is, the bolts 129A and 129B are removed for removal of the guide frames 120A and 120B, whereupon the tapping screws 141A and 141B are removed for removal of the lid members 67A and 67B. And the lid members 67A and 67B are turned through 180 degrees sos that the wedging elements 70A and 70B are opposed to the pawl portions 63a and 63b.

In this state, whenthe lid members 67A and 67B are lowered, the wedging elements 70A and 70B act on the inner surfaces of the pawl bodies 63A and 63B, thereby outwardly opening these pawl bodies 63A and 63B against their elasticity so as to release the pawl portions 63a and 63b from the locked portions 73A and 73B. Subsequently, the free roller 13 is pulled directly upward, whereupon the bearing bodies 71A and 71B fitted on the roller shaft 12 are removed upward from the recesses 60A and 60B and so are the lid plates 67A and 67B. Thereafter, the bearing bodies 71A and 71B.fitted on the roller shaft 12 of a new another free roller 13 are dropped from directly above into the recesses 60A and 60B and then the lid members 67A and 67B are set in position.

In the case where the guided members are wooden pallets 108, the metal guide plates 132 are sufficient for satisfactory guide, but if the pallets 108 are made of some other material (such as resin) or special objects 30 are to be directly transferred, the guide plates 132 will be replaced by those made from a material suitable for the situation. In the construction represented by the resin guide plates 130, this can be effected by lengthwise shifting the resin guide plates 130 to move the locking portions 131 for Insertion or extraction relative to the locking grooves 122A and 122B. In the construction represented by the metal uide plates 132, replacementcan be effected by mainpulating the counter-sunk bolts 135 for tightening or loosening; in this case, the patch plates 133 and counter-sunk bolts 135 as well as the guide frames 120A and 120B can be used as such.

When long-sized objects to be transferred such as one shown at 30 in Fig. 28 are to be handled, it is possible to increase the roller pitch P and decrease the number of transmission units 40 each comprising a free roller 13 and a transmission roller 21. This can be realized by removing the free roller 13 and other parts as described above, loosening the bolts 10A and 10B, moving the support frames 9A and 9B by the guides portions 2A and 2B in the direction of the transfer path 23, and tightening the bolts 10A and 10B for fixing with respect to the nuts 3A and 33 which have been moved integrally therewith. At this time, unnecessary free rollers 13 and support frames 9A and 9B are removed.

In the above, the entire length of the transfer path 23 has been described as serving as a drive region 31; this, however, as shown in Fig. 27, can be switched between non drive regions 32 and drive regions 31, the details of the switching operation being the same as in the second embodiment previously described with reference to Fig. 11.

As pointed out in the above embodiment, when the support frame 85 for supporting the free end side of the L shaped plate 35 is provided, part of the load on the side 0 associated with the L-shaped plate 35 can be supported, and hence the attachment by the bolt 10A and the shape of the transmission unit 40 can be maintained satisfactory for a long time. Further, the support frame 65 can be utilized for the attachment of a photocell device and a solenoid valve and also utilized as the main member for the duct as described above.

As for the guide frames 120A and 120B, a wide shape shown in Fig. 29 may be employed.

Figs. 34 through 38 show a sixth embodiment.of the invention.

As in the previous embodiments, transmission units 40, such as the one shown in Fig. 21, each comprising a support shaft 18, a sprocket 20, a transmission roller 21 and an air cylinder device 75, etc., which are supported by a support frame 9A, are disposed in opposed relation to most of the plurality of free rollers 13. Brake units 151 are disposed relative to some free rollers 13.

The brake units 151 are constructed in the same way as the transmission units 40 and, as shown in Fig. 35, each brake unit has a support shaft 152 extending along a roller axis 17, said support shaft 152 being fitted at one end thereof In a bearing portion 19 so that it is vertically swingable. A cylindrical boss member 154 is fixed to the support shaft 19 by a key 153, and a brake body 155 of urethane rubber Is fixed to the boss member 154. The brake body 155 Is cylindrical and Is arranged so that its outer peripheral surface can be contacted with the lower region of the outer periphery of the free roller 13. The brake body together with the boss member 154 can be circumferentially displaced for change of phase so as to change its active portion, thereby coping with problem of wear. An air cylinder device 156 for moving the brake body is disposed between a cylinder rubber support 157 attached to the other side of the support shaft 152 and the transverse plate of an L-shaped plate 35. When the boss member 154 Is shaped to have a flange portion 158 made integral therewith as by cutting off the teeth of the sprocket 20 of the transmission unit 40, the flange portion 158 can be engaged with the upper side of the chain 24.

The free rollers 13 each paired with a transmission unit 40 or brake unit 151 as described above are arranged at intervals of a pitch P ona main frame 1, whereby a transfer path 23 is defined by the group of free rollers 13. The numeral 161 denotes buckets, which are an example of an object to be transferred.

Free rollers 13 each paired with a transmission unit 40 or brake unit 151 are divided into a plurality of groups a, b, cr n, each group consisting of seven units, and are controlled group by group. That Is, It Is arranged that a first supply and discharge hose 165 serially connecting the air cylinder devices 75 for the transmission units 40 and a second supply and discharge hose 166 serially connecting the air cylinder devices 156 for the brake units 151 can be alternatively connected to an air supply hose 169 from an air supply device 168 through a 5-port solenoid valve 167.

The numeral 170 denotes a regulator, and 171 denotes a silencer. Each of the groups a, b, c. n is provided with an item presence detector 172 of photoelectric or other type.

Transfer operation based on the above construction will now be described.

In Figs. 34 and 36, in all groups a, b, c. n, the solenoid valves 167 are switched to connect the air supply hoses 169 to the first supply and discharge hoses 165, and the support shafts 18 are swung upward by the extension of said air cylinder devices 75 to press all transmission rollers 21 from below against the corresponding free rollers 13. At this time, the chain 24 is constantly driven by the motor 29 and hence all sprockets 20 engaged with the chain 24 are rotating around the axes of the support shafts 18.

The transmission rollers 21 are contacted with the lower regions of the outer peripheries of the free rollers 13 to thereby forcibly rotate the free rollers 13, so that buckets 161 can be transferted on the transfer path 23 in which the entire length is made to serve as a drive region. At this time, the second supply and discharge hoses 166 are opened and the support shafts 152 are swung downward under their own weights on the basis of the amounts of contraction of the air cylinder devices 156 for the brake units 151, thus moving the brake bodies 155 away from the free rollers 13.

Therefore, no brake action is created and hence the corresponding free rollers 13 are allowed to rotate freely with the travel of the buckets 161.

As shown by the group b in Fig. 37, for example, the solenoid valve 167 is switched to connect the air supply hose 169 to the second supply and discharge hose 166 and, as shown in Fig. 35, the support shaft 152 Is swung upward by the extension of the air cylinder device 156 to press the brake body 155 from below against the corresponding free - roller 13, whereby free rotation of this free roller 13 can be prevented. Thereby, it is possible to brake a bucket 161 to prevent it from being transferred. In addition, when the brake body 155 is pressed as Indicated by a phantom lin J in Fig. 34, the transmission roller 21 is spaced away as indicated by a phantom line K.

As shown in Fig. 37, for example, when the bucket 161 is in the storage state In the group b, a bucket 161 which has come in as it is transferred by the group a which Is in the drive state is detected by the Item presence detector -M 172 as indicated by a phantom line R. As a result of this detection signal and the detection signal from the group b, the solenoid valve 167 for the group a is automatically switched so that, as described above, the transmission roller 21 is separated from the free roller 13 and the brake body 155 is pressed against the free roller 13. Thereby, the bucket 161 is braked and stopped without colliding with the preceding bucket 161 as indicated by a phantom line S.

If the bucket 161 in the group b is carried out, the detection signal from the item presence detector 172 disappears, whereby the solenoid valve 167 for the group a is automatically switched for drive so that the bucket 161 is transferred to the group b.

Fig. 38 shows another example of arrangement of a transmission unit 40 and a brake unit 151. In this example of arrangement, the transmission unit 40 is disposed below one end of the free roller 13 while the brake unit 151 is disposed below the other end. According to such arrangement, the free roller 13 which is being driven can be braked.

5'

Claims (14)

WHAT IS CLAIMED IS:

1. A roller conveyor comprising:

a main frame, support frame means attached to said main frame so that its position lengthwise of said main frame can be changed as desired, free rollers rotatably attached to the top of said support frame means for transferring objects to be transferred, support shafts disposed in the lower region.of said support frame means and extending along the axes of said free rollers, said support shafts being vertically swingable attached to said support frame means, a transmission roller and a driven wheel which are supported on each said support shaft and rotatable as s unit.

upward movement imparting means attached to said support frame means and operatively connected to said support shafts to move the latter upward, thereby pressing said transmission rollers against the lower regions of the outer peripheries of said free rollers, driving means associated with said main frame and operatively connected to said driven wheels to drive the latter.

2. A roller conveyor as set forth in Claim 1, wherein z the driving means is an endless chain.

3. A roller conveyor,as set forth in Claim 1, wherein the upward movement imparting means is a spring.

4. A roller conveyor as set forth in Claim 1, wherein the upward movement imparting means is a cylinder, which is operated to contact the transmission roller with the lower region of the outer periphery of the free roller or separate it therefrom.

5. A roller conveyor as set forth in Claim 4, including a driving region in which the transmission roller is in contact with the free roller and a non-driving region in which the transmission roller is out of contact with the free roller, said regions being arranged lengthwise of the free roller.

6. A roller conveyor as set forth in Claim 2, wherein the support frame means, Support shaft, transmission roller, driven wheel and upward movement imparting means form a transmission unit, a plurality of such transmission units being arranged in spaced relationship with each other lengthwise of the main frame, with a cover for the chain being removably installed between adjacent transmission units.

7. A roller conveyor as set forth in Claim 1, wherein the support frame means comprises a first support frame associated with one end of the shaft of the free roller associated with the transmission roller and a second support frame, separate from said first support frame, for supporting the other end of the shaft of the free roller remote from the transmission roller, said first support frame having a plurality of vertically spaced locking holes which, when the diameter of the shaft of the free roller Is changed, is capable of supporting one end of the shaft of a new free roller at a different level corresponding to the change in the diameter of the shaft, said second support frame being adapted to be attached to the main frame in a plurality of directions, said second support frame having a plurality of locking grooves associated with the direction of attachment for supporting the other end of the shaft of said free roller, said locking grooves being arranged so that their groove bottoms for supporting the other end of the shaft of said free roller are associated with the levels of said locking holes, said locking grooves each having projection means which serves as a stopper to prevent the other end of the shaft of the free roller from slipping off.

8. A roller conveyor as set forth in Claim 2, wherein the chain is supported by chain support means integral with the main frame, and a guide rail fitted In said chain support means.

9. A roller conveyor as set forth in Claim 1, including a pair of bearing bodies capable of supporting one end and the other end of the roller shaft of a free roller, the support frame means comprising a pair of support frames disposed correspondingly to one end and the other end of the roller shaft of the free roller, each support frame being formed with a recess for receiving the bearing body from above and pawl portions for preventing the bearing body from slipping off.

10. A roller conveyor as set forth in Claim 1, including an annular boss portion integral with the driven wheel and arranged to transmit the rotative power from said driven wheel to the transmission roller, vent hole means formed in said annular boss portion to extend therethrough along the support shaft, and vane means formed near the opening of said vent hole means.

11. A roller conveyor as set forth in Claim 4, including a flexible body adapted to expand under the pressure of fluid fed to a cylinder so as to vertically swing the support shaft, and a cover body installed on the side associated with the support shaft to cover said flexible body from above.

12. A roller conveyor as set forth in Claim 1, wherein a plurality of said support frame means are attached to the main frame, said roller conveyer Including a transmission unit which comprises a first support shaft, a transmission roller, a driven wheel and first upward movement imparting means in first support frame means, said roller conveyor further including a brake unit, said brake unit comprising second support frame means to which a second free roller Is attached, a second support shaft vertically swingably attached to the lower portion of said second support frame means, a brake body attached to said second support shaft, and second upward movement imparting means attached to said second support frame means and engaged with said second support shaft to move said second support shaft upward, thereby pressing said brake body against the lower region of the outer periphery of said second free roller.

13. A roller conveyor as set forth in Claim 1, wherein the support frame means comprises a pair of support frames disposed correspondingly to one end and the other end of the roller shaft of a free roller, said roller conveyer including a transmission unit which comprises one support frame, a first support shaft in said one support frame, a transmission roller, a driven wheel, and first upward movement imparting means, said roller conveyor further including a brake unit, said brake unit comprising the other support frame, a second support shaft vertically swingably attached to the lower portion of said other support frame, a brake body attached to said second support shaft, and second upward movement Imparting means attached to said other support frame and engaged with said second support shaft to tto move said second support shaft upward, thereby pressing said brake body against the lower region of the outer periphery of said free roller.

14. A roller conveyor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Pubhshed 1988 at The Patent Office, S te House, 66,71 Iligh Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Offtee, Saless'Branch, St Mary Crav. OrDinL't.nr W. PAA