US3837470A

US3837470A - Apparatus for transferring objects

Info

Publication number: US3837470A
Application number: US00350185A
Authority: US
Inventors: A Dunkin
Original assignee: Diamondhead Corp
Current assignee: Diamondhead Corp
Priority date: 1972-04-05
Filing date: 1973-04-11
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24
Also published as: AU5409273A; DE2317111B2; FR2179156B1; CA983061A; GB1390891A; JPS5634298B2; DE2317111C3; FR2179156A1; DE2317111A1; JPS4916282A; US3765037A; IT984290B; CH568755A5; SE385657B; BR7302405D0; AU470004B2

Abstract

An improved belt drive and control mechanism for an object transfer apparatus of the type in which different phases of transfer operation are effected by selective linear travel in transfer apron forming flight portions of an endless belt. The flight length of a loop formation in the apron forming endless belt is varied concurrently with alternate energization of primary and secondary belt brakes to achieve the desired flight travel in the transfer apron. The secondary belt brake includes a brake shoe and a braking roller. The braking roller is supported and actuated by a pair of bell cranks in conjunction with a pair of roll brake actuating cams. The peripheral configurations of the cams are identical and the cams are mounted on a cam shaft so that corresponding points are displaced by 180*. The braking roller may perform both a braking function and a tracking or steering function depending upon the relative positions of the actuating cams. A detecting and control arrangement serves to automatically actuate the cam shaft to correct belt tracking.

Description

ite States atent 91 1111 3,837,470 Dunkin 1 Sept. 24, 1974 APPARATUS FOR TRANSFERRING Primary Examiner-Richard A. Schacher OBJECTS lnventor: Albert Dunkin, South Norwalk Conn.

Assignee: Diamondhead Corporation,

Mountainside, NJ.

Filed: Apr. 11, 1973 Appl. No.: 350,185

Related US. Application Data Division of Ser. No. 241,1 11, April 5, 1972, Pat. No.

References Cited UNITED STATES PATENTS Assistant Examiner-Jeffrey V. Nase Attorney, Agent, or Firm-Lane, Aitken, Dunner & Ziems [5 7] ABSTRACT An improved belt drive and control mechanism for an object transfer apparatus of the type in which different phases of transfer operation are effected by selective linear travel in transfer apron forming flight portions of an endless belt. The flight length of a loop formation in the apron forming endless belt is varied concurrently with alternate energization of primary and secondary belt brakes to achieve the desired flight travel in the transfer apron. The secondary belt brake includes a brake shoe and a braking roller. The braking roller is supported and actuated by apair of bell cranks in conjunction with a pair of roll brake actuating cams. The peripheral configurations of the cams are identical and the cams are mounted on a cam shaft so that corresponding points are displaced by 180. The braking roller may perform both a braking function and a tracking or steering function depending upon the relative positions of the actuating cams. A detecting and control arrangement serves to automatically actuate the cam shaft to correct belt tracking.

7 Claims, 33 Drawing Figures PAI E NIEU 30241914 HEET 01 0F 1 F/GJ,

Y 3 IO PAIENTEnszrzmsm sum on HF 11 FIG/6.

PAIENImsEmIsu v 3.837,- 470 saw near 11 LOAD OUT LOAD IN UNLOAD OUT UNLOAD m PAIENIEDSEPZMQM QONQE QONQI CROSS REFERENCE TO RELATED APPLICATION This is a division of application Ser. No. 241,111, filed Apr. 5, 1972, now US. Pat. No. 3,765,073.

BACKGROUND OF THE INVENTION This invention relates to improvements in apparatus for transferring objects, and more particularly, it concerns an improved apron tracking and control arrangement for object moving apparatus of the type illustrated and described in US. Pat. No. 3,579,672 issued on May 25, 1971 to Laurel A. K011 and Walter Crook, Jr. and assigned to the assignee of the present invention.

The object moving apparatus disclosed inthe aforementioned U.S. Pat. No. 3,579,672 has been demonstrated to be a most highly effective tool for use in transferring non-ambulatory patients from a hospital bed or other surface on which they are initially reclined to a mobile carriage by which they may be supported and then transferred to a second surface such as a surgical table, an x-ray table or another bed. In essence, the apparatus of the patent includes, in addition to a load carrying mobile base structure, a pair of laterally translatable superposed, sheet-like apron supporting separator members about which a pair of upper and lower fabric-like aprons are trained. The aprons are established by endless belts formed of fiberglass or nylon reinforced teflon and are independently controlled in,

a manner such that during lateral extension of the separators out over a bed and under a patient to be transferred, the respective flight portions of the upper and lower aprons which contact the patient and the bed remain stationary relative thereto and thus isolate both the patient and the bed from frictional contact with the laterally extending separator plates. When the patient is fully positioned on the assembly of aprons and separator plates, the condition of the upper apron is changed so that the upper flight portion thereof, in physical contact with the patient, will move in the same direction and at the same linear speed as the separator plates during retraction to transfer the patient from the bed or other surface on which he was initially reclined to the apparatus. The lower flight portion of the lower apron is fixed to the base structure of the apparatus so that it remains stationary with respect to the surface of the bed also during the' retraction of the separator plates. Thus, during loaded retraction of the separator and apron assembly, the lower flight portion of the upper apron slides relative to the upper flight portion of the lower apron with which it is in frictional contact. Such sliding motion between the belts is accommodated by the low friction characteristics of the reinforced teflon from which they are made and the generation of unwanted static electricity is avoided by impregnating one or both of the belts holding the aprons with a conductive material such as graphite.

While the apparatus disclosed in the aforementioned US. patent thereof represents, in terms of basic operating principles, a major breakthrough particularly in the handling or transfer of non-ambulatory hospital patients, working experience with the apparatus has demonstrated a need for improvement in the belt control and drive mechanism of the apparatus.

A problem experienced with the apparatus for which the improvement of this invention is primarily intended was as a result of improper tracking of the endless belt establishing the upper apron. Though edge guiding the endless belt was provided initially to overcome the problem of the belt creeping endwise of the machine, the stress is imposed on edges of the belt was found with extended operation to cause an unacceptable amount of belt wear and breakage.

While the background of experience gained with working embodiments of the apparatus disclosed in the aforementioned patent demonstrates the desirability and the need for improvement, the recognition and discussion of those problems is not intended in any way as a criticism of the highly desirable basic operating principles of that apparatus.

SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, an improved apron tracking and control mechanism for object transferring apparatus of the aforementioned type is effected by training an endless beltestablishing the upper of two superposed aprons about relatively stationary and movable rollers to form a storage loop formation capable of flight length variation so that full control over movement or non-movement of selected flight portions of the belt can be achieved by regulating the on or off condition of primary and secondary belt retaining brakes.

The secondary belt brake, referred to also as a roll brake because of its structural organization, is energized or closed against the belt only when the main brake is deenergized or open. When closed, the roll brake ensures a proper take-up of slack as well as movement of the upper apron as a unit with the upper apron supporting separator. Structurally, the roll brake is established by mounting the relative stationary roller of the rollers forming the belt storage loop formation for a slight measure of adjustable movement with re spect to a fixed brake shoe. Hence, roll brake energization is effected by a clamping movement of the roller against the fixed shoe. The braking roller is capable of an angular adjustment from a neutral or nonbraking position to effect tracking steerage of the belt during certain phases of machine operation. Adjustment of the braking roller for both braking and steering functions is carried out by a single cam shaft operated by a single electrical motor controlled automatically by system of limit switches and control circuitry.

Among the objects of the present invention, therefore, arepthe provision of an improved object transferring apparatus of the type referred to; the provision of an improved apron drive andthe provision of a novel tracking or steering mechanism for endless belts; and the provision of a mechanically improved,easily assembled, maintenance free object transfer apparatus of the type referred to above and having particular utility in the field of handling non-ambulatory hospital patients.

Other objects and further scope of applicability of the present invention will become apparent to those skilled in the art'from the detailed description of a preferred embodiment to follow taken in conjunction with the accompanying drawings in which like parts are designated by the same reference numeral.

FIG. 1 is a perspective view of the object or patient handling apparatus incorporating the improvements of the present invention;

FIG. 2 is an enlarged fragmentary and cut-away plan view of the apparatus shown in FIG. 1;

FIG. 3 is an elevation showing one of two end plates incorporated in the apparatus according to the present invention and as seen on line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary elevation of the end plate shown in FIG. 3;

FIG. 5 is a fragmentary cross-section taken on line 5-5 of FIG. 4;

FIG. 6 is a fragmentary cross-section taken on line 6-6 of FIG. 4;

FIG. 7 is a fragmentary perspective view in partial cross-section on line 7-7 of FIG. 2;

FIG. 8 is an enlarged fragmentary and elevation similar to FIG. 3 and partially cut-away;

FIGS. 9A-9D are schematic illustrations depicting in four phases of operation, the basic apron and belt drive components of this invention as those components would be seen in line 9-9 of FIG. 2 but at a greatly distorted scale in the interest of a clear illustration of operating principles as distinguished from particular structure;

FIG. 10 is a fragmentary cross-section taken on line 10-10 of FIG. 8;

FIG. 11 is a fragmentary cross-section taken on line 11-11 of FIG. 8;

FIG. 12 is a fragmentary cross-section taken on line 12-12 of FIG. 8;

FIG. 13 is a fragmentary cross-section taken on line 13-13 of FIG. 12;

FIG. 14 is an enlarged plan view of the moving roller carriage of the present invention as seen on line 14-14 of FIG. 3;

FIG. 15 is an elevation of the carriage shown in FIG. 14 as it would be seen on line 15-15 of FIG. 3;

FIG. 16 is an enlarged fragmentary cross-section taken on line 16-16 of FIG. 2;

FIG. 17 is an enlarged fragmentary perspective view in partial cross-section on line 17-17 of FIG. 16 and further illustrating components shown in FIG. 16;

FIG. 18 is a fragmentary perspective view illustrating the combined belt braking and steering mechanism of the invention;

FIGS. 19A-22A are fragmentary side elevations illustrating the respective positions of the braking roller of the present invention in relation to corresponding positions of control cams thereof;

FIGS. 198-228 are fragmentary and somewhat schematic plan views showing the relative positions of the components shown respectively in FIGS. 19A-22A;

FIG. 23 is an enlarged fragmentary cross-section taken on line 23-23 of FIG. 18;

FIG. 24 is a cross-section taken on line 24-24 of FIG. 23;

FIG. 25 is a front elevation showing the master control unit for operation of the improved apparatus of this invention; and

FIG. 26 is a circuit diagram illustrating the control logic by which the improved apparatus of this invention is operated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although this divisional application of US. Ser. No. 241,111, now US. Pat. No. 3,765,037, is concerned primarily with a novel tracking or steering mechanism for endless belts which may be employed in any endless belt device, in order to facilitate an understanding of the invention, the preferred embodiment is illustrated and described in the overall environment of the object transfer apparatus for which the mechanism is especially suited.

As shown in FIG. 1, the apparatus includes a mobile base structure or chassis having a lower pedestal section 10 supported on swivel mounted caster wheels 12 and an upper transfer section 14 supported for vertical adjustability with respect to the pedestal by a lifting arm 16. A pair of laterally translatable, superposed upper and lower

transfer apron assemblies

18 and 20, respectively, as well as the drive mechanism for these assemblies, are carried by the upper section 14. The improvement of the present invention is primarily concerned with operating components contained in the upper section 14, the organization of the pedestal 10 and the lifting arm 16 being essentially the same as the prior art.

Although much of the frame structure incident to providing structural integrity in the upper section 14 has been omitted from FIGS. 2 and 3 of the drawings, the frame members on which major operating components are supported in the upper section 14 are shown in these figures to include a pair of substantially identical end plates or castings 22 connected in longitudinally spaced relation by a load carrying deck structure 24 and a back guide beam 26. The frame structure including these components among others (not shown) is enclosed by an outer shell 28 for purposes of sanitation, safety and decor. As is shown most clearly in FIGS. 5 and 7 of the drawings, the deck structure 24 in the disclosed embodiment is formed of a series of adjacent box-beam members 30 to provide a continuous upwardly facing horizontal surface for supporting the

apron assemblies

18 and 20.

Because the fundamental object transfer operation of the apparatus shown in the aforementioned US. Pat. No. 3,579,672 is retained in accordance with the present invention, the construction and function of the

apron assemblies

18 and 20, in themselves, parallel quite closely corresponding units in the apparatus of that prior patent. Hence, the lower apron assembly 20, as shown in FIGS. 5 and 7, is established by a lower flexible sheet-like separator plate 32 having a thin, faric-like apron 34 trained over the top, bottom, leading and trailing edge surface portions thereof. The material from which the apron 34 is formed is preferrably nylon reinforced teflon, the terminal ends of which are sewn or otherwise formed about welting to establish end anchoring enlargements or

ribs

36 and 38. As shown most clearly in FIG. 7, the end anchorage 36 is received in an upwardly facing groove formed in a specially formed box section 40 so as to be firmly secured to the leading edge of the deck 24 by an inverted L- shaped retaining member 42. The anchorage 38 at the opposite end of the apron 34 is received in a similar groove or channel formed in the retaining member 42 and secured by an outer retaining strip 44. The strip 44 and the member 42 may be secured in place by suitable means such as screws 46 accessible from the front or leading edge of the deck 24 thereby to facilitate removal and replacement of the apron 34. The apron 34 is slidable with respect to the surfaces of the separator plate 32 such that lateral translation of the separator plate from a retracted position overlying the deck to an extended position will be accompanied by relative travel between the apron and separator in a manner that will be discussed more fully below.

The upper apron assembly 18 includes an upper apron 48 trained about an upper separator plate 50 which, for purposes of the present invention, may be considered as identical to the lower separator plate 32.

As shown in FIG. 5, both

separator plates

32 and 50 are provided at their inboard edge with longitudinally extending tabs 52 adapted to be secured such as by a pin 54 to spaced tabs 55 on a connecting bracket 56. The central or body portion of the bracket 56 is provided with a guide block 58 received slidably in a guide groove 60 machined or otherwise formed in the end plate 22. A bifurcated formation 62 on the bracket 56 enables direct connection of the bracket by pins 64 to a drive chain 66 of a type conventionally known as a bicycle chain.

As shown most clearly in FIGS. 2-4, the drive chain 66 is trained in endless fashion about a series of

idler sprockets

68, 70, 72 and 74 and a drive sprocket 76 keyed or otherwise nonrotatably fixed to a drive shaft 78 journalled at opposite ends in the respective end plates 22 and extending the full length of the upper section 14 of the apparatus. A reversible electric motor 80 appropriately supported from the frame of the upper section 14 is coupled directly to the shaft 78 by a chain and sprocket drive 82. Thus it will be appreciated that operation of the motor 80 to rotate the shaft 78 and drive sprockets 76 in one direction will effect a lateral translation of the bracket 56, as well as the

separator plates

32 and 50 connected directly to the bracket, from a retracted position in which the bracket is located at the inboard end of the deck as shown in FIG. 3 outwardly until the bracket approaches a position in proximity to the idler sprocket 70.

The upper apron 48 is established by flight portions of an endless belt, the complete flight path of which will be described more fully below with reference to FIGS. 9A-9D of the drawings. In connection with the structural illustration of FIGS. 3 and 8, however, it will suffice to note that the endless belt forming the upper apron 48 is trained about a pair of moving or

translatable rollers

84 and 86 journalled at opposite ends in carriage members 88 suspended from grooved tracks 90 formed in the end plates 22. Also journalled in each of the end carriage members 88 is a pinion sprocket 92 located between upper and lower pairs of upper idling guide rolls 94 and 95, respectively. Also inengagement with the pinion sprocket 9 2 is a fixed length of bicycle chain 96 secured at its ends to the end plate 22 by

adjustable brackets

98 and 100. The chain 96 functions with the pinion sprocket 92 in the manner of a rack and is retained in driving engagement with the pinion by the guide rolls 95 as shown most clearly in FIG. 3.

Other structural components having a direct bearing on the basic object transfer operation of the aprons l8 and 20 to include a primary or main brake 102, a secondary or roll brake 104 and a pair of

idler guide rollers

106 and 108. An understanding of the general object transfer operation can be had by noting that the main brake 102 includes a fixed shoe or friction pad 110 secured along the bottom surface of the back guide beam 26 and a movable friction pad 112 secured along the upper surface of a retractable brake shoe beam 114. Thus it will be appreciated that a belt portion passing between the

pads

110 and 112 will be held stationary with respect to the pad 110 as well as the remaining frame structure of the upper section 14 when the pad 112 is moved against the belt and the pad 110. Conversely, separation of the

pads

110 and 112 will allow a belt to move freely along the bottom of the back guide beam 26.

The roll brake 104 includes an arcuate friction pad and shoe 116 secured directly to a front face portion of the back guide beam 26 and is adapted to cooperate with the cylindrical surface of a brake roller 118 rotatably supported at opposite ends by a pair of independently movable bell crank elements 120 having arms 121- and 122 and pivoted on studs 124 fixedly mounted on the end plates 22. Hence it will be appreciated that a belt portion trained about the brake roller 118 in a way to be situated between the roller and the shoe 116 may be held against movement by bringing the brake roller 118 and that portion of the belt into engagement with the fixed arcuate shoe 116. The roll brake 104 as well as the main brake 102 are operated in synchronism by a cam system to be described below and carried on a single car'n shaft 126 also journalled at opposite ends in the end plates 22.

In FIGS. 9A-9B of the drawings, the components described above are shown schematically to depict the improved apparatus of the present invention in four phases of object transfer operation respectively; that is, load out, load in unload out, unload in. Also in these figures the complete flight path of the respective belts establishing the upper apron 48 and the lower apron 34 are represented by lines provided with arrow heads to indicate direction of travel of flight portions or runs in the belts or with spaced dots on those flight portions which remain stationary during certain phases of operation. Hence, and as mentioned above, the lower apron 34 is formed as a simple loop of belt material trained about the top, bottom andedge surface portions of the lower separator plate 32 to establish in the lower apron an upper flight portion 344: and a lower flight portion 3411. Because the lower flight portion 34b is secured by the above-described anchorage including the strip 44, the lower flight portion 34b remains stationary in relation to the deck 24 and other portions of the upper section 14 of the disclosed apparatus during all four phases of operation. The upper flight portion 34a of the lower apron, however will move in the-same direction as the lower separator plate 32 but at twice the linear speed thereof. Hence, in the load out and unload out phases shown respectively in FIGS. 9A and 9C and wherein the separator plate 32 is translated from an initial retracted position overlying the deck 24 to an extended position overlying a bed or other surface (not shown) on which the object or person to be transferred is initially reclined, the flight portion 34b of the lower apron will function to insulate the lower separator plate 32 from frictional contact with that bedor other Initial surface. The upper flight portion 34a, during these phases of operation, will move outwardly in the same direction as theseparator plate 32 but at twice the speed thereof as a result of the mechanics of the lower apron assembly. Conversely, during retracting movement of the separator plate 32, as during the load in and unload in phases shown in FIGS. 93 and 9D, operation of the lower apron is a mere reversal of that in the other two phases.

The length and flight path of the endless belt forming the upper apron 48 is considerably greater and more complicated than that of the lower apron 34. As can be seen readily in FIGS. 9A-9D, an uppermost flight portion 48a extends from the back guide beam 26 to the leading edge of the upper separator plate 50 and merges with a lower apron flight portion 48b extending from the leading edge of the upper separator plate to the idler guide roller 106. After a short vertical flight section 480 between the

idler rollers

106 and 108, four

flight portions

48d, 48e, 48f and 48g, which makeup a storage loop formation, are established by training the upper apron forming endless belt about the moving

rollers

84 and 86 mounted on the carriage members 88 and about the braking roller 118. The lowermost flight portion 48g passes between the main

brake shoe pads

110 and 112 and merges with a return flight 48h extending along the back surface of the back guide beam 26. Operation of the main brake 102 and of the roll brake 104 is controlled so that during the load out phase illustrated in FIG. 9A, the main brake 102 is energized to hold the

flight portions

480, 48g and 48h in a stationary condition. The deenergized condition of the roll brake 144 allows the brake roller 118 to function as an idler roller during this phase of operation. Because the upper flight portion 48a of the upper apron 48 is held in a stationary condition with respect to the upper section 14 of the apparatus and thus with respect to the bed or other surface adjacent to which the apparatus is placed, the upper flight portion 48a of the upper apron will function to isolate the upper support plate 50 from frictional contact with the object to be transferred in a manner similar to that described in connection with the lower flight portion 34b of the lower apron relative to the surface on which the object or person is initially reclining. As a result of this frictional isolation, both

apron assemblies

18 and 20 will advance between the object or person and the surface on which the object or person is resting without transmission of lateral forces from the

separators

32 and 50 to either that surface or the person, respectively.

To retract the object or person, now located centrally over the

extended separator plates

32 and 50, operation of the drive motor 80 and drive chains 66 is reversed so that the separator plates will move inwardly toward the back guide beam 26 whereas the carriage and

rollers

84 and 86 will move in an opposite outward direction. In addition to this reverse movement of the separator plates and carriage in the load in phase as illustrated in FIG. 98, however, the condition of the

brakes

102 and 104 is reversed so that the roll brake 104 is energized whereas the main brake 102 is deenergized. Accordingly, both upper and

lower flight portions

48a and 48b of the upper apron 48 will move as a unit or at the same speed and in the same direction as the upper separator plate 50 to carry the object back onto the deck 24. Movement of the other flight portions of the belt forming the upper apron 48 in the load in phase is believed self-explained by reference to the arrows and dots superimposed on the line representation the belt in the drawing.

Operation of the

aprons

34 and 48 during the unload out phase to transfer an object or person from a position of support on the deck 24, outwardly to a bed or other surface to which transfer is desired, involves essentially only a reversal of separator plate travel as compared with the load in phase depicted by FIG. 98. Similarly, the unload in phase is illustrated in FIG. 9D is carried out by reversing separator plate travel from that of the load out phase of FIG. 9A. In light of the illustration in FIG. 9, it is believed that further description of these phases of operations is unnecessary to a full understanding of the operation of the apparatus to effect a transfer of an object or person to and from a position of support over the deck 24.

As shown most clearly in FIGS. 14 and 15, the carriage members 88 located at opposite ends of the moving

rollers

84 and 86 are substantially identical, each including a hanger plate having a pair of laterally spaced guide rollers 132 cantilevered inwardly of the plate 130, a pair of bearing plates 134 spaced outwardly of the hanger plate 130 and a pair of roller mounting brackets 136 and 138 for supporting the

rollers

84 and 86, respectively. The pinion sprocket 92 is appropriately journalled between the hanger plate 130 and the lower bearing plate 134 as shown in FIG. 15 as are the

guide rollers

94 and 95 by which the lower run of the drive chain 66 and the rack chain 96 are constrained in driving engagement with the pinion sprocket 92 as described above with reference to FIG. 3. The guide rollers 132 are adapted to ride in the outwardly facing groove 90 in the end plates 22 which are cut out as at 140 (FIG. 3) to accommodate carriage suspension from the end plates in this manner.

The support of the four respective ends of the

rollers

84 and 86 from the brackets 138 is shown in FIG. 15 to include a spherical bearing mount 142 engagable in a socket ring 144 thereby to permit unimpeded rotation of the

rollers

84 and 86 about their respective axes irrespective of whether those axes are in alignment with the axis of the bearing mount 142. The importance of this bearing organization can be appreciated by reference to FIG. 14 wherein it will be noted that the

rollers

84 and 86 are constrained to an arcuate configuration by a series of cradle rollers 146 journalled in brackets 148 supported on the front face of each of a pair of box beams 150 fixed at opposite ends to the brackets 136 and 138. The vertical thickness of the beams 150 relative to the

rollers

84 and 86 can be seen in FIG. 15 to be slightly less than the diameter of the rollers. The arcuate geometry of the

rollers

84 and 86 facilitates a belt steering or tracking function which forms the subject matter of this application to be described in more detail below.

As mentioned above with respect to FIG. 8, the fixed friction pad 110 is fixed at the lower surface of the back guide beam 26 and extends along the length of this beam between the end plates 22. The movable friction pad 112 is carried on the upper surface of a retractable brake shoe beam 114 also extending the length of the machine between the end plates 22 in generally parallel relation to the friction pad 110. As shown most clearly in FIGS. 12, 13 and 18, the brake shoe beam 114 is constructed in truss-like fashion to include a longitudinally extending upper flange member 152, on which the pad 112 is directly supported, and a lower tension strut 154. The beam or truss thus constituted is connected near its ends to a pair of plate like arms 156 pivotally supported from the end plates 22 by inwardly cantilevered studs 158. A coil spring 160 having end arms connected respectively to an end plate mounted pin 162 and a pin 164 mounted on the arm 156 serves to bias the arms 156 and thus the brake shoe beam 14 to a deenergized position wherein the pad 112 is moved downwardly away from the fixed pad 110. As can be seen most clearly in FIG. 18, the beam 114 is prestressed in such a manner that the upper surface of the flange 152 and correspondingly the friction pad 112 is constrained to an arcuate configuration in which the central portion of the pad 112 along its length approaches the fixed pad 110 more closely than at the ends.

The actuating mechanism for the main brake 102 is shown most clearly in FIGS. 8, 10, 12 and 18 of the drawings to include near each end of the brake beam 114 a pair of lever arms 166 and 168 independently pivoted on a stud 170 cantilevered inwardly from each of the end plates 22. The arm 166 is formed with an eccentric boss portion 172 tapped to receive a set screw 174 positioned to engage an abutment surface 176 carried by the arm 168. The arm 166 supports at its distal end, a roller 178 in peripheral engagement with a downwardly concave surface 180 in a bearing block 182 secured to the underside of an extension of the flange 152 of the beam 114 by suitable means such as a screw 184 as may be seen in FIG. 12 of the drawing. Thus the weight and downward bias of the arms 156 by the springs 160 will insure constant engagement of the set screw 174 with the abutment 176 so that the arms 166 and 168, though adjustable with respect to each other, operate in the manner of a single bell crank.

The distal end of the arm 168 carries a follower roller 186 to engage the peripheral surface 188 of a cam 190 keyed for rotation directly with the cam shaft 126. The profile of the cam surface 188 is shown in phantom lines in FIG. 8 of the drawings to be generally heartshaped thereby to establish a low radius point 188a in one quadrant merging with a relatively high radius point extending in circular fashion through the remaining three quadrants about the axis of the cam shaft 126.

The construction of the roll brake 104 and the mechanism by which it is actuated in the perfonnance of its braking function can be understood by reference to FIGS. 8, 11 and 12 and 18 of the drawings. As men-- tioned above, the brake roller 118 extends approximately the length of the apparatus between the end plates 22 and is supported at opposite ends bythe bell cranks 120. As shown most clearly in FIG. 11 of the drawings, the roller 118 carries at each end a bearing socket 192 in free rotational engagement with a spherical bearing member 194' carried by a stub axle 196 in such a way that axial misalignment of the roller 1 18 and the stub axle will not in any way impede rotational freedom of the roller 118. The stub axle 196 is supported in cantilever fashion from the upstanding arm 121 on each of the bell cranks 120 and supports, at a point intermediate its length between the end of the roller 118 and the arm 121, a pivotal bracket 198. The bracket 198 is connected by screws 200 or other suitable means to a backup beam 202 equipped with sets of cradling rollers (not shown) similar in all respects to the eradling rollers 146 described above with respect to the moving

rollers

84 and 86. In this instance, however, the cradling rollers and the beam 202 constrain the brake roller 118 to a truly linear configuration along its length and hence prevent flexing of the roller against the force of the upper apron forming belt and also against braking pressure during movement of the roller 118 toward the brake shoe 116 as shown in FIG. 18. The end of the bracket 198 opposite the end thereof connected to the beam 202 extends as a guide tab 204 slidably received in a slot or groove 206 formed in the end plate 22. The primary function of the guide tabs 204 is to support the beam 202 in a horizontal position behind the brake roller 118 in light of the pivotal connection of the brackets on the stub axle 196. As shown in FIG. 18, the lower horizontal arm 122 of the bell crank carries a follower rollers 206 in position to engage the surface of one of two roll

brake actuating cams

208 and 210 non rotatably fixed or keyed at opposite ends of the cam shaft 126.

In addition to functioning as a component in the roll braket 104, the brake roller 118 functions as a steering roller by which proper tracking of the upper apron forming belt is maintained throughout its flight path and particularly over the

flight portions

48a and 48b during their travel relative to upper separator plate 50. The manner in which this steering or tracking function is superimposed on the braking function of the roller 118 may be understood by reference to FIGS. 19-22 of the drawings. In FIGS. 19A-22A, cam shaft 126 and the roll

brake actuating cams

208 and 210 near opposite ends thereof are shown in each of four operating positions to which the shaft 126 is rotated by control means to be described below. In FIGS. 19B-22B, the effect that cam shaft positioning on the respective positioning of the brake roller 1 18 relative to the fixed shoe 116 and the cam shaft 126 is illustrated schematically in plan views.

With reference specifically to FIG. 19A, it will be seen that the peripheral configurations of the two

cams

208 and 210 are identical and define at four mutually perpendicular radii, throw points N, S-l, B and S-2. Though identical in peripheral configuration,

cams

208 and 210 are reversed or mounted on the shaft 126 in opposite directions so that the points N and B are aligned whereas the points S-1 and 8-2 on the

respective cams

208 and 210 are displaced by Also it might be noted that the throw of each of the cams is equal at points S-2 and B as well as maximum at these two points. The throw of each cam is smallest at the radius point 8-] whereas the throw of each cam at the radius point N is intermediate the throwsat S-2 or B and 5-1. Thus, in the cam shaft position illustrated in FIGS. 19A and 198, wherein the bell crank follower roll 206 overlies the radius point N, the roller 118 is positioned away from the brake shoe 116 and in parallel relation thereto. Hence in the context of the braking function of the roller 126, a deenergized or neutral, position is depicted by the relation of components in FIGS. 19A and 19B.

In FIGS. 20A and 20B of the drawings, the relationship of the cam shaft 126, roller 118 and brake shoe 116 is illustrated during a braking or energized condition of the roll brake 104. This. condition is brought about by rotatably indexing the cam shaft 126 to a position in which the radius points B on both

cams

208 and 210 underlie the follower roll 2% on the bell crank 120. In light of theequal and maximum throw of both

cams

208 and 210 in this angular position of the shaft 126, the bell cranks 120 operate to move the roller 118 into contact with the fixed shoe 116 and also so that it is disposed in parallel relation with respect to the cam shaft 126 as well as the other rollers about which the endless belt forming the upper apron 48 is trained.

The manner in which a belt steerage function is superimposed on the roller 118 can now be understood by reference to FIGS. 21A22B of the drawings. As shown in FIGS. 21A and 218, when the cam shaft 126 is rotated so that the raduis point S-2 on the cam 208 underlies the follower 206 on a bell crank 120 on one end of the roller 118, whereas the radius point 5-1 on the other cam 210 underlies a similar follower roll on the other bell crank associated with the other end of the roller 118, a canted or non-parallel orientation of the roller results. Moreover, it will be noted that the roller 118 is out of contact with the brake shoe 116 during this position as can be seen in FIG. 21B. Inasmuch as the upper apron forming belt is trained about the roller 118 (see FIGS. 9) the canted position of the roller 118 will effect steerage of the belt so that it will track to the right in relation to a reference direction of from left to right in FIG. 218. A similar steering orientation of the roller 118, but in an opposite direction, is efected by the orientation of the

cams

208 and 210 shown in FIGS. 22A and 22B.

In relation to the overall operation of the object transfer operation as described above with respect to FIGS. 9A-9D, the belt steering function depicted in FIGS. 21 and 22 can be operative or effective only during the load out" and unload in phases of operation shown respectively in FIGS. 9A and 9D. Because the roll brake 104 is required to be energized during the load in and unload out phases of operation illustrated respectively in FIGS. 98 and 9C, which phases require the roller 118 to be held in parallel contacting relation with the fixed brake shoe 116, the roller 118 is, in effect, disabled from a steering function. Further it is to be noted that because both upper and

lower flights

48a and 48b of the apron 48 move as a unit with the upper separator plate 50 during these phases, the likelihood of edgewise creeping of the apron forming endless belt'during these phases is minimal if not nonexistent. This can be appreciated by comparing the relative travel of the apron flights 48a and 4812 with respect to the upper separator 50 during the load in and unload out" phases with the increased relative movement of those flight portions with respect to the upper separator during the load out and unload in phases. During these latter phases the steering function of the roller 118 is both available and more likely to be needed.

Although a complete understanding of the operation of the apparatus described above will be had from the description to follow in conjunction with the circuit diagram of FIG. 26, reference is first made to FIGS. 2, 3, 16-18 and 23-25 wherein the physical relation of various electrical control and sensing components are shown with respect to described structural components. For example, in FIG. 3 of the drawing, a pair of

limit switches

212 and 214 are shown mounted in spaced relation on at least one of the end plates 22 in a position to be tripped by a tab 216 depending from the carriage member 88 supported from that end plate. The limit switches 212 and 214 operate to terminate operation of the main drive motor 80 at opposite ends of carriage member travel and correspondingly at opposite ends of the travel of the separator plates 32 and 50in moving between their retracted and extended positions. As shown in FIGS. 16 and 17, the position of the endless belt forming the upper apron 48, particularly the flight portion 48c thereof in relation to the longitudinal dimension of the back beam 26, is followed by a pair of guide blocks 218 supported on a slide rod 220 in a position to be engaged by the edges of the upper apron fonning belt at the flight portion 480. The rod 220 is supported from the back of the deck 24 by bearing tabs 222 (see also FIG. 8). Plungers 224 supported from the guide blocks 218 extend through slide bearings 226 in the end plates 22 in a position to engage left and right

hand limit switches

228 and 230 respectively. The limit switches 228 and 230, as shown in FIG. 16 are supported by brackets 232 adapted to be secured by appropriate means to the end plates 22.

As shown in FIGS. 2 and 3 of the drawings, the cam shaft 126, which is journalled at opposite ends in the respective end plates 22 is adapted to be driven rotatably by a drive motor 234 and drive chain 236 mounted beneath the deck 24 and adjacent one of the end plates 22. To detect the indexed position in which the cam shaft 126 is placed by the motor 234, a shaft rotation sensing assembly shown in FIGS. 18, 23 and 24 is em ployed. Specifically, an insulating mount 238 of generally U-shaped configuration is supported about the shaft 126 and carries four magnetically actuated

reed switches

240, 242, 244 and 246 adapted to be actuated by a pair of

permanent magnets

248 and 250 carried by the shaft. As shown in FIGS. 23 and 24, the

magnets

248 and 250 are both axially spaced and angularly spaced at right angles with respect to one another so that for any given increment of shaft rotation, only one of the four reed switches will be actuated at one time.

In addition to the component sensing and control devices thus described, a manually operated master control unit 252 is provided; an exemplary embodiment thereof being illustrated in FIGS. 1 and 25 of the drawings. As will be seen in FIG. 25, the unit 252 is equipped with an extensible cord 254 connected electrically with control circuitry located in the pedestal 10 of the apparatus and also equipped with six push button switches 256a-b carrying legends corresponding to the operational phase effected by depression. In this context, it will be noted that four of the

push buttons

256a, 256b, 256e and 256f correspond directly to the phases of operation described above with respect to FIGS. 9A-9D. The push buttons bearing the legends up and down" enable manual control over the lifting beam 16 (see FIG. 1) operated by an electric motor which, though not shown in FIG. 1 of the drawings, is illustrated schematically in the circuit diagram of FIG. 26 and designated by the reference numeral 258. The motor 258 and the drive transmission thereof by which the upper portion 14 of the apparatus is elevated or lowered by the lifting beam 16 is fully disclosed in the prior art.

In light of the foregoing description, it will be appreciated that overall operation of the several components illustrated and described will be carried out by operation of the main drive motor 80, the cam shaft drive motor 234 and in some measure by the lifting motor 258, the latter being used only to position the

aprons

18 and 20 at the desired elevation. As shown in FIG. 26, the

push buttons

256a and 256d bearing respectively the legends up" and down would operate the motor 258, which is reversible, in either of one of two directions depending on which of these buttons is depressed. Although in actual practice, the circuitry of this motor is likely to be more sophisticated than that depicted in FIG. 26, the basic operation of the motor will be apparent to one skilled in the art from the schematic showing of FIG. 26.

Similarly, the main drive motor 80 may be operated under the control of a conventional motor control and power supply circuit 259 in turn controlled by signals generated by the depression of any one of the

switch buttons

256a, 256b, 256e or 256f to advance the separator plates and roller carriage members 88 in the appropriate direction to effect the operation phase indicated by the respective legends carried by these push buttons. The limit switches 212 and 214 which are depicted as normally closed and in the power supply circuit to the motor 80 in FIG. 26, may in practice be connected electrically in other parts of the overall circuit by which the motor is operated. In any event, the limit switches, being normally closed, will permit operation of the reversible drive motor 80 in either of two directions until the limit switch is opened by the carriage and the separator plates reaching their maximum limits of travel.

Operation of the main brake 102, the roll brake 184 as well as steering operation of the brake roller 118, as mentioned above, are controlled by indexing rotation of the cam shaft 126 by the motor 234. In the disclosed embodiment, the motor 234 is unidirectional and controlled by logic circuitry including four AND

gates

260, 262, 264 and 266. In other words, the motor 234 will operate to rotate the cam shaft as long as any one of the four AND gates 260-264 is enabled by a specific combination of conditions of the push buttons 256, the

limit switches

228 and 230 and the reed switches 240-246 which in FIG. 26 bear legends corresponding to function which will occur at the respective indexed locations of the shaft 126. Tus, the AND gate 260 will be enabled to effect operation of the drive motor only if during depression of either of the push buttons 256a or 256f to bring about respectively the unload in or load in phases of operation (both of which require energization of the roll brake 104), the reed switch 246 is opened to indicate that the cam shaft 126 is in a position other than that in which the roll brake is energized. This operation is caused by the AND gate 260 being enabled only by the combination of a signalfrom an OR gate 268, in turn enabled by either of the push buttons 256b or 256f, and a signal from an inverter 270 which provides an output signal only when the reed switch is not closed. Hence, if the cam shaft 126 is in a position to close the reed switch 246, no operation of the motor 234 will occur upon depression of the push button 256b or 256f. Moreover, if the cam shaft is located at a positionso that the reed switch is not closed, the motor 234 will drive the cam shaft until the reed switch 246 is closed by angular alignment of the permanent magnet 250 therewith.

The AND gate 262 will be enabled to operate the motor 234 only upon the following conditions being present: the reed switch 240 must be opened to indicate the cam shaft 126 is in a position other than that required for positioning the brake roller 118 in a neutral position (see FIGS. 19A and 19B); neither of the tracking switches 228 or 230 must be energized; and either one of the

push buttons

256b or 256e must be depressed to command the unload in or load out" phases of operation respectively. The enabled state of the AND gate 262 under these conditions is brought about by the combination of an inverted signal from the reed switch 240 through an inverter 241 and the signal from an AND gate 272. The AND gate 272, in turn, is enabled to pass such a signal only upon receiving signals from

inverters

274 and 276, the input to which is effected by the open condition of the

microswitches

228 and 230, respectively and a signal from an OR gate 278 with which the push buttons 256b and 2562 are connected. Hence operation of the motor 234 will be initiated by the AND gate 262 only when one or the other of the

push buttons

256b or 256e is depressed, the

microswitches

228 and 230 are open and the reed switch 240 is open. Conversely, operation of the drive motor by the AND gate 262 will terminate upon a change in any of these conditions of the enumerated control components.

As previously indicated, the brake roller 118 can accomplish its steering or tracking function only when the roll brake 104 is in its deenergized condition as during the load out and unload in phases of operation. Operation of the motor 234 to position the cam shaft in a track right or track left position is effected by a control signal from the AND gates 264 and 266 respectively. In this connection, it is to be noted that the term track left implies a condition in the upper apron forming belt, specifically in the flight portion 480 thereof, which requires a shifting of that flight portion to the left in order to move the belt to a desired central position between the end plates 22 wherein neither of the limit switches is closed by the plungers 224 on the guide blocks 218. The condition commanding a track left function, therefore, is present when the flight portion 48c causes the right hand limit switch 230 to be closed. Correspondingly the track right limit switch 228 is physically located at the left hand end of the machine in the same directional context. Hence, the AND gate 264 will be enabled by a closure of the track left limit switch 230 during a depression of either of the

push buttons

256b or 256e to enable the OR gate 278 in the manner described above and by signal from an inverter 280 which is enabled only when the reed switch 244 is not in its closed position. Thus only when the cam shaft is in a position such that the magnet 250 closes the reed switch 244 will the AND gate 264 be disabled assuming the presence of signals resulting from the closure of the limit switch 230 and the

push buttons

256b and 256e. Operation of the motor 234 under a control signal from the AND gate 266 will be effected in a similar manner though by closure of the limit switch 228 and by the'presence of signals from an inverter 282 with which the reed switch 242 is associated and from the OR gate 278. f i

In light of the organization of the brake roller 118 and its related control components, it will be appreciated that any tendency for the belt forming the upper apron 48 to creep edgewise (from end to end of the upper chassis section 14) as a result of unpredictable and uneven load forces during operation will be offset or corrected by the steering function of the brake roller. An additional measure of belt tracking facility is provided, in accordance with the present invention, to overcome unwanted edgewise creepage of the upper apron forming belt as a result of manufacturing tolerances in the geometry of the belt. To illustrate, if the endless belt forming the upper apron is envisaged as a truly cylindrical tube, then the belt would track through its entire flight path so along long the rollers and other surfaces defining that flight path were truly parallel. If on the other hand, the belt geometry is envisaged as slightly conical, which in actual practice is more likely to be the case as a result of manufacturing tolerances, the belt would have a tendency to creep in the direction of the edge defining the smaller end of the cone, assuming the components establishing its flight path to be in true parallel relation relative to each other. To accommodate any tendency for a given belt to define a slightly conical tube rather than a true cylindrical tube, the back guide beam 26 is mounted to the end plates or castings 22 in a manner to enable the back surface thereof over which the flight path 48h is trained to be adjusted to an alignment out of parallel with the remaining rollers and surfaces over which the belt forming the upper apron 48 is trained. Hence, as shown most clearly in FIGS. 8 and 17 of the drawings, the ends of the back guide beam 26 extend as mounting tabs 284 and are secured to the back surfaces of the end plates 22 by screws 286 over one or more shims 288. By adjusting the thickness of the shims 288, it will be appreciated that the rear surface of the back guide beam 26 can be adjusted to a position out of parallel with the leading edges of the

separator plates

32 and 50, for example, to accommodate a slightly concial geometry of the belt resulting from manufacturing tolerances. Moreover it will be appreciated that this adjustment can be made as each upper apron forming belt is placed on the apparatus.

Thus it will be seen that as a result of the present invention, there is provided an improved object or patient handling apparatus by which the abovementioned objects among others not expressly mentioned, are completely fulfilled. Also it will be appreciated by those skilled in the art that numerous variations and/or modifications of the embodiment illustrated and described herein can be made without departing from the true spirit and scope of the present invention.

In addition, it will be apparent to those skilled in the art from the disclosed embodiment that the organization of the brake roller 118 and the actuating means by which it may be positioned in either of two radially spaced parallel positions or in either of two canted or inclined positions could be incorporated and have utility in a combined steering and tensioning mechanism for endless conveyor belts.

It is expressly intended therefore, that the foregoing description is illustrative of a preferred embodiment only, not limiting, and that the true spirit and scope of the present invention be determined by reference to the appended claims.

I claim:

1. In an object transfer apparatus employing an endless belt, the combination comprising: a plurality of normally parallel rollers for guiding said belt through a flight path, and means supporting one of said rollers for adjustable movement between a pair of radially spaced parallel positions and also between a pair of oppositely inclined belt shifting positions in which the axis of said one roller is at an angle with respect to the others of said guide rollers, said supporting means comprising a pair of independently pivotal bell cranks on opposite ends of said one roller, one arm of each of said cranks being connected to said one roller, the other arm of each of said cranks having a cam follower thereon, and cam means in operative relation with the follower on each of said crank members for adjustably moving said one roller.

2. The apparatus recited in claim 1 wherein said cam means comprises a rotatable cam shaft and a pair of cams mounted on said shaft for rotation therewith, each of said cams having the same peripheral camming surface configuration, said cams being reversed on said shaft to provide in two indexed positions of said cam shaft, different throw radii which is the same in both said cams thereby to locate said one roller in either of said two radially spaced parallel positions, and in two other index positions of said cam shaft, two other different throw radii displaced from each other on the respective cams by an angle of about the axis of said cam shaft and being operative thereby to adjust said one roller to either of said belt shifting positions.

3. In an object transfer device employing an endless belt, the combination comprising:

a plurality of normally parallel rollers for guiding said belt through a flight path, and positive positioning and retaining means supporting one of said rollers for adjustable movement between a pair of radially spaced parallel positions and also between a pair of oppositely inclined belt shifting positions in which the axis of said one roller is at an angle with respect to the others of said guide rollers, said supporting means comprising a pair of cam follower members each connected to said one roller and cam means in operative relation with said cam follower members for adjustably moving said one roller.

4. The apparatus recited in claim 3 wherein said cam means comprises a pair of cams, each of said cams having the same peripheral camming surface configuration; rotatable means for supporting said cams for rotation therewith, said cams being reversed in relationship to each other to provide in two indexed positions of said rotatable means, different throw radii which is the same in both said cams thereby to locate said one roller in either of two radially spaced parallel positions, and in two other index positions of said rotatable means, two other different throw radii displaced from each other on respective cams by an angle of 180 about the axis of said cams and being operative thereby to adjust said one roller to either of said belt shifting positions.

5. In an object transfer device employing an endless belt, the combination comprising:

a plurality of normally parallel rollers for guiding said belt through a flight path, and positive positioning and retaining means supporting one of said rollers for adjustable movement between a pair of radially spaced parallel positions and also between a pair of oppositely inclined belt shifting positions in which the axis of said one roller is at an angle with respect to the others of said guide rollers, wherein said supporting means comprises a pair of independently pivotal members connected on opposite ends of said one roller; and cam means in operative relation with said pivotal members for adjustably moving said one roller.

6. The apparatus recited in claim 5, wherein said cam means comprises a pair of cams, each of said cams having the same peripheral camming surface configuration; rotatable means for supporting said cams for rotation therewith, said cams being reversed in relationship

Claims

2. The apparatus recited in claim 1 wherein said cam means comprises a rotatable cam shaft and a pair of cams mounted on said shaft for rotation therewith, each of said cams having the same peripheral camming surface configuration, said cams being reversed on said shaft to provide in two indexed positions of said cam shaft, different throw radii which is the same in both said cams thereby to locate said one roller in either of said two radially spaced parallel positions, and in two other index positions of said cam shaft, two other different throw radii displaced from each other on the respective cams by an angle of 180* about the axis of said cam shaft and being operative thereby to adjust said one roller to either of said belt shifting positions.

3. In an object transfer device employing an endless belt, the combination comprising: a plurality of normally parallel rollers for guiding said belt through a flight path, and positive positioning and retaining means supporting one of said rollers for adjustable movement between a pair of radially spaced parallel positions and also between a pair of oppositely inclined belt shifting positions in which the axis of said one roller is at an angle with respect to the others of said guide rollers, said supporting means comprising a pair of cam follower members each connected to said one roller and cam means in operative relation with said cam follower members for adjustably moving said one roller.

4. The apparatus recited in claim 3 wherein said cam means comprises a pair of cams, each of said cams having the same peripheral camming surface configuration; rotatable means for supporting said cams for rotation therewith, said cams being reversed in relationship to each other to provide in two indexed positions of said rotatable means, different throw radii which is the same in both said cams thereby to locate said one roller in either of two radially spaced parallel positions, and in two other index positions of said rotatable means, two other different throw radii displaced from each other on respective cams by an angle of 180* about the axis of said cams and being operative thereby to adjust said one roller to either of said belt shifting positions.

5. In an object transfer device employing an endless belt, the combination comprising: a plurality of normally parallel rollers for guiding said belt through a flight path, and positive positioning and retaining means supporting one of said rollers for adjustable movement between a pair of radially spaced parallel positions and also between a pair of oppositely inclined belt shifting positions in which the axis of said one roller is at an angle with respect to the others of said guide rollers, wherein said supporting means comprises a pair of independently pivotal members connected on opposite ends of said one roller; and cam means in operative relation with said pivotal members for adjustably moving said one roller.

6. The apparatus recited in claim 5, wherein said cam means comprises a pair of cams, each of said cams having the same peripheral camming surface configuration; rotatable means for supporting said cams for rotation therewith, said cams being reversed in relationship to each other to provide in two indexed positions of said rotatable means, different throw radii which is the same in both said cams thereby to locate said one roller in either of two radially spaced parallel positions, and in two other index positions of said rotatable means, two other different throw radii displaced from each other on respective cams by an angle of 180* about the axis of said cams and being operative thereby to adjust said one roller to either of said belt shifting positions.

7. The apparatus recited in claim 6, wherein said rotatable means comprises a single rotatable cam shaft.