US1556586A

US1556586A - Industrial truck

Info

Publication number: US1556586A
Application number: US613944A
Authority: US
Inventors: William C Carr
Original assignee: AUTOMATIC TRANSP ATION Co
Current assignee: AUTOMATIC TRANSP ATION Co; AUTOMATIC TRANSPORTATION Co
Priority date: 1923-01-20
Filing date: 1923-01-20
Publication date: 1925-10-13
Anticipated expiration: 1942-10-13

Description

C, CARR INDUSTRIAL TRUCK Filed Jan. 20, 1923 4 Sheets-Sheet 1 J M/ent Attor y Oct. 13, 1925. 1,556,586

w. c. CARR INDUSTRIAL TRUCK Filed Jan. 20, 1923 4 Sheets-Sheet 2 Pay. 2

b 9 Attorney Oct. I W. C. CARR INDUSTRIAL TRUCK Filed Jan. 20. 1923 4 Sheets-Sheet Inventor W/LL/l/VC. CARI? -92 W. C. CARR INDUSTRIAL TRUCK Filed Jan. 20, 1925 4 Sheets-Shem 4 illllllllll lllll has rmntedoaQ 13,1925.

UNITED STAT wnmrax chain, or serum, YORK, assrenon TO THE AUTOMATIC TRANS- ron'ra'nou comm, or BUFFALO, new YORK, aconronarron' or ARIZONA.

INDUSTRIAL TRUCK.

Application filed January 20, 1928.1 Serial 1T0. 618,945

To all whom it may concern:

Be itknown that 1, WILLIAM C. Care, a

citizen of the United States, residing at 2933 Main Street, Buffalo, in the county of Erie and State of NewYork, have invented a @new and useful Improvement in Industrial Trucks, of which the following is a specification.

This-invention relates to improvements in electricallyv operated industrial trucks such as are provided with load supporting platforms and are used in manufacturing establishments for the quick and easy transport of objects or, materials from one point to another, the loads beingplaced on the platforms either directly or by means of loading skids.

i The inventionsecures the advantages of maximum flexibility in the regulation of the speed of operation, any desired operating speed being available, the use of slow and safe accelerating speed which is particularly desirable when fragile or breakable objects are being transported, certainty and maximum' facility of control, a substantially f longer eflicient life of the truck mechanism,

the elimination of arcing between the relatively movable contacts of the switches, re-

duction of the cost of operation and main,

tenance, and the greatest degree of safety, involving protection to the, truck and its load, objects along the line of travel and the person of the operator. 7 The principal ob'ect of the invention is to A further object: to provide mechanism, which, having the characteristics stated,

"makes possible an exceedingly simple and compact switch or nization, an advantage of value owing to t e necessity for lightness and compactness in the organization of the mechanism of industrialrtruck's which must be capable .of easy and. certain handling in small and congested areas where frequently required. w a

A further object is to provide means whereby the proper sequence of'operations of the motor controlling featuresas'responsive to the operation oi the controlling eletheir use is emp oyed in ment is positively and automatically insured and compelled;

With theabove objects in view the invention consists in novel features of structure and combination, which will be set forth in detail as thedescription proceeds.

A referred embodiment of the invention is i1 ustrated in the-accompanying drawings, wherein:

Fi ure 1 is a side elevation in which the usua parts of the truck are shown in broken lines and the parts in'whichthe features of the invention are incorporated are shown in full lines.

Figure 2 is an elevation of the switch mechanism and certain connections for oper ating the resistor, the front cover of the switch mechanism being removed.

Figure 3- is, an end view'of the switch mechanism, the casing therefor being shown in section.

Figure 4 is a section onthe line 4i of Figure 1 showing the brake and its operating connections.

Figure 5 is a diagram of the'wiring of the motor, switch mechanism and'resist-or.

Figures 6 and 7am an end view and an elevation, respectively, showing a modifica tion' of the connections for operating the resistor. 7

ES PATENT ,oFF cE.

Figures 8 and 9 are similar views showing another modification of the same.

Figures 10 and 11' are similar views showing ajfurthermodification of the same.

The truck includes a frame lsupported rear wheels 2 are shown), a propelling motor 3 connected by suitable gearing 4 (not shown as to details) to the rear wheels, a load carrying platform 5 located in front of the wheels2- and an operators latform or ste 6 located behind thewhee s 2. A suitable upright .framework, generally designated 7 isarrange d/betw'eenthe platform 5 and step 6 as the su portfor the various.

parts necessary fort e operation of the oo by front and rear wheels (whereof only the truck, these 'arts including the motor 3 and gearing 4, t e storage-batteries mounted in a box 8 and the switch mechanism 9 which may be conveniently arranged adjacent the rear wall of the box 8.

1 The speed of the motor 3 isregulated entirel by avariable' resistance 10 which is OOJgIHHCtiOD with a normally cIosed main swi is operated by a con- .shown or described in detail.

trolling element having no connection with said main switch. The variable resistance is preferably of the compression type, which, belng well known, does not r mm to be or resent purposes it will be suflicient to point out that as applied to industrial trucks a removable adjusting rod 11 which extends .through'one end of the container.

The current flows to the motor 3 through a mainswitch 9 which differs fromthe controller ordinarily employed in that it does not have variable speed contacts and further in that it encompasses the functions of the usual separate reversing switch. For the regulation of the direction of the motor the main switch includes four

movable contacts

12, 13, 1 4 and 15 and four

stationary contacts

12, 13, 14 and 15. The

contacts

12, 13, 14 and 15 are preferably carried by a drum 16 fixedly mounted on the switch shaft 17. There is also-provided a swltch 9 b which the resister 10 may be short circuite 'i. e.', which may be substituted for the resister in the'circuit of the main switch, and which, in the construction shown and preferred, comprises 'a movable contact 18, carriedv by a drum 19 loosely mounted on the shaft 17 and a pair of

stationary contacts

18 and 18" with which the contact 18 maybe engaged. The

contacts

13 and 14 are wired to the

contacts

15 and 12 respectively and are arranged to go the

respective contacts

13 and 14 sini taneously with the engagement of the

contacts

15 and 12 with the

respective contacts

15 and 12 as when the motor is to be driven in one direction,

. say forward. To provide for the operation the drum 16'b'eing of the motor in the reverse direction the contacts 15; and. 12 are formedwhereby, as engagedv the

contacts

15 and 12 tively,fthey fmajy be simultaneously ng g with the contacts 14; and 13 a the

contacts

14 and 13 from ,the

n

14 and 13 and thereafter to establish the engagement. with said 14! and 13 of the

respective contach

15 and 12.

1 The ration of the compression resistor is such at'thev M111 is forced. inward to secure progre ml-velyfbetter contact of the graphite disos md the redsta'nce val-1E inversely'with the eompremiomthat 'i's'to say the as the pressure on the discs is increased by the continued inward movement of the rod 11 and vice versa. To prevent waste of current the rod 11 ma have a degree of outward movement su ficient to break the contact of the discs and thus 0 n the circuit through the resistor. Accor in to the invention the operations of the. switch 9" and rod 11 are coordinated whereby the contact 18 engages the contacts 18 and 18' to short circuit the resistor when, 7 and not before, the resistance of the discs has been reduced to minimum and disengages the contacts 18 and '.j18" as soon as the resistance commences to build ,upfroln minimum.

Fi re 5 shows ,a wiring diagram from whic 1 the foregoing general features of operation will be apparent. One terminal of the battery 20 is connected to a wire 21 havmg a branch 21 which is connected to an electrode 22 in permanent contact with the rod 11 and a branch 21 which is connected to the contact 18". The other terminal of the resistor 10 is connected by a wire 23 to the contact 13 and by a wire 24 to the contact 18. Assuming that the switch 9 is set for the forward drive of the motor and that the current is passed through the resistor the circuit maybetraced as follows: one terminal of battery 20, wire 21, wire 21, electrode 22, rod 11, resistor 10, wire 23,

contacts

13, 13, 15 and 15, wire 25 and.

branches

25 and 25", field windings of motor 3, branch'wires 26 and 26 to wire 26,

contacts

12, 12, 14V and 14, wire 27, brush 28, armature 29, brush 30, andwire 31 to the other terminal of battery 20. If, however, with the current again passed through the resistor,'the switch be set forv the reverse drive of the motor the current of course flows through the field windings of the mo-- tor in the opposite. direction and the circuit may be traced as follows: one terminal of battery 20, wire 21, branch 21, elec-' trode 22, rod 11, resistor 10, wire 23, contacts13, 12 and 12, 7 wire 26, branches. 26 and 26", field windingsof 'motor 3,.

branch wires

25 and 25",wire 25, contacts 15, 15and 14, wire 27,brush 28, armature 29, brush 30, and wire 31 to the other terminal of the battery 20. Assuming that the resistor is short circuit'ed by the engagement of the contact 18' with the

contacts

18 and 18" the circuits are traced as in the preexcept that the current in: no stead of flowingthrough the resistor to the wire 23 is shunted-by-the branch 21", con-- tactsIS, 18 and 18 and wire 24 to the wire 23.

As shown and preferred the controlIer. shaft 17 is arr-angled horizontally and the resistor 10 exten I parallel to said, shaft.- The shaft 17 is 'ourn'alled in the end walls 32 of the switc casing 33 which casing encloses the bar 34 upon' whichthe sta- I sguared openin 'tive. contacts 13 an isfmoved to its downward limit, and in an.

.15 are mounted. The shaft 17 is operated by hand to establish the engagement of the

contacts

12, 13, 14 and 15- in the manner described and for this purpose is extended throu h an end wall of t e casing 33 and rovi ed with an operating handle 35. The andle is formed at one end with a inwhich the squared end the shaft 1 may be conformably engaged whereby the handle may be removed from the shaft. *The

contacts

12, 13, 14 and 15 are so arranged. that the

contacts

12 and 15 are at all times engaged with the contacts 12 and .15, the

contacts

13 and 14, only, are engaged with the respective contacts 13' and 14 when the drum 16 is moved to its upward limit, the contacts '12 and 15, only, are en aged with the respec- 14" when the drum intermediate position of the drum the contacts 13' and 14 are not engaged by either pair of

contacts

13 and 14, or 12 and 15. It is desirable that the handle 35 be removable from the shaft 17 only when the drum 16 is in its intermediate or off position.. For this purpose a cylindrical cas 'ing or gate 36 may be secured to a frame part in surrounding relation to the shaft 17 and the hub portion of the handle 35; the gate 36 has a circumferential slot 37 through which the handle 35 projects and a longitudinal slot 38 extending to its outer end and through which said handle may be removed in the neutral 17. In. order that the um 16 may be secured in any of its-three positions but with out obstruction'to its ordered movement a suitable friction latch may be provided which, as shown and preferred, consists of a spring pressed ball 39 fitted in the bearing for the shaft 17 atone side of said shaft and engageable in recesses 40 formed or provided inthe' adjacent end of said drum.

With themafin switch set in either of its I Y. on positions the-movement of the truck is wholly subject. a. single controlling element which preferably comprises a pedal 41 mountedlin juxtaposition to the optiff-According to the invention mechanism, 'providedfor connecting this tolthecompression rod 11 of the resistogl to the short circuiting switch 9 andf'preferablyalso to the brake in su h -wa'ylthat the operations of these elements 'co-ordinated to one another andarer'esponsive In the construction preferred the compresto a single movement of the pedal in either direction.

sion rod11 is outward a spring 42 operatin and is forced inward by an axially movable stem 43 which includes a shank rovid with quick acting threads 44 workmg in a relatively stationary nut 45. When position of the shaft thestem 43 is turned about its longitudinal axis it will move axially in one direction or the other according to the direction in which it is turned. In one directon of its axial movement it will engage the rod 11 and force the same inward in opposition to-the spring 42, thereby progressively to increase the compression of the discs of the resistor.

discs becoming spaced from one another at one or more points whereby the current path through the resistor is broken. The-rod 11 is preferably provided with an insulated tip 46 of hard metalto take the contact of the stem 43. The nut 45 is preferably adjustable whereby the stem 43 may be set as desired in relation to the rod 11. purpose said nut has threaded engagement in a fixed bracket 47 and is provided with a suitably formed adjusting head 48 by which it may be turned. Aflatch 49 of suitable form is provided to hold the nut 45 against accidental displacement and preferably consists of a stud screw fitted the bracket 47 and engaging in any one of 'a series of ref cesses formed in the peripheral face of thehead'48.

The stem 43 is provided with an arm 50 by which it may be rocked and in the construction'preferred is connected to the drum 19 of the short circuiting switch by means of a link 51 pivoted to said arm and to a lug on said drum. The hub portion of the arm 50 preferably has a tapering fit on the stem 43 and is keyed thereto, being held against end- For this n wise displacement by a nut 52.threaded upon the end of said stem. The connections of the link 51 have lateral and end play sufficient to permit said link to act without binding in consequence of the cndwise'movement of the arm 50 with the stem 43.

Linkage connections are preferably used to connect the pedal 41 to the arm 50. These include an upper two-armed lever 53 and a lower lever 54 preferably provided with an angularly extending third arm 55. i The pedal 41 is connected by a link 56 to an arm of the lever 53, the opposite arm of which is connected by a link 57 to one of the alining arms of the lever 54.3 The opposite alining arm of the lever 54 is connected by a link 58 to the arm 50 at a point-beyond the connection of the link 51.

The pedal 41 is normally held raised byla 7 suitable spring 59 and by virtue of the connections described its movement in either direction is positively transmitted. The

contacts of the short circuiting switch are engaged only when the pedal is fully deressed. The extremes of compression of the discs of the resistor are obtained .in the extreme positions of the pedal, the maximum'compression being effected when the pedal is fully lowered and the minimum or, more exactly, the zero of compressionbeing efi'ected when the pedal is fully raised. The rod 11 is moved throughout the movement of the pedalin either direction, being moved inward whenthe dal is lowered and outward when the pe al is raised. The engage ment of the contacts of the short circuiting switch is the final effect in the movement of the pedal to its extreme downward limit and the disengagement of said contacts is the in- :itial effect in the movement of the pedal from its extreme downward limit.

In any movement of the'. pedal between its extreme upper position anda lower position short of For this its extreme lower position no operation of the short circuiting switch is produced, merely an idle movement of the contact 18, and the resistor 10 functions throughout, the resistance being varied according to the direction and extent of the pedal movement. The invention also includes the control of the brake by the pedal 41 in connection with its movements to control the operations of the short circuitin switch and the resistor. (purpose t e arm of the lever 54 is utilize The brake is preferably of the construction shown which consists of a pair of semi-circular shoes engageable with a drum 61 fitted on the shaft of the motor 3. The shoes 60 are pivotally connected as at 62 whereby they may be spread apart or provided with extensions 63, which are acted on by a brake-o crating springv 64. As

shown a laterally irected rod 65 carried by one of the extensions projects slidably through an opening in the other upon which the spring 64 directl bears, the spring be-, ing mounted on sai rod and exerting its thrust against a nut orhead at the free'end of the rod. The shoes 60 are disengaged from the drum 61 by a brake releasing cam 66 arranged between and'act ing on the extensions 65 and mounted on a rock shaft 67 having support by means of a suitable bearing increased speed 68. The shaft 67 is provided with-a lever arm '69 which is connected by a link 70 to the arm 55-.--' As the pedal 41 -is lowered to provide for the. propulsion of the .truck at v t e cam '66 is turned so as tospreadthe shoes 60 and hold them disfrom the drum 61. As the pedal is 1'81 to reducejthe' speed at which the truck isdiventhecam66isturnedsoastopermit the shoes 60 to move toward one another under the pmure, of the spring 64; Substantially at the time the pedal reaches its extreme upper position the spring 64 efiects' the complete engagement of the shoes 6t) 'upon the drum 61, thereby to arrest the rotation of the motor shaft.

It will thus be seen that when the'pedal.

with the resistance sufiiciently great to prevent the fiow of current to the motor inany substantial degree. When it is desired to move the truck "the pedal is depressed (the action of its supportin spring preventing it from being depresse too rapidly) with the first effect of. releasing the brake and the continuous effect of progressively reducin the resistance in the element 10. The true thus starts with a slow and safe accelerating speed and its rate of movement can be stead- -ily increased or decreased as required. As-

suming that it is desired to drive the truck at fullispeed the pedal is depressed to its downward limit and when this is reached the short circuiting switch is closed, .operating in the present embodiment, in the manner previously explained, to cut out the resistor 10. 'Atthe timethe short circuiting switch is closed the resistance of the element 10 has been reduced to minimum so that the differ ence of potential between the current flowing through the resistor and the'full'strength of the current flowingthrough the short circuiting switch is very small from which it follows that operation of the short circuiting switch, either in closing or o ening, will be without arcing. When it is esired to brin the truck to a stopthe pedal is released an as it completes its upward movement effects the application of the brake and at the same time opens the circuit of resistor 10. I e It will be noted that thespeed of the truck is controlled wholl by the pedal 41 and that all phases of speed regulatlon are automatically taken care of. The truck, moreover, in the embodiment described, has no fixed speeds but may be driven at any d desired, the selection and control of t e s 'eed being analo ous, both in manner and e ect, to that obtained by the foot operated accelerator of an automobile operated by an inthe otor at the ternal combustion engine. This facility of speed control also insures safety 'ofoperation, since the speed. may be instantly selected as conditions'ma'y require and indefinitely maintained at. as low a rate asmay be found necessary and since the hands of the operator are left free so that he may readily steady himself on the platform 6.

The slow, gradual and steady application of currentto the motor incident to the system of control described is of further advantage in that shocks are eliminated and vibrations minimized so that all parts of the truck mechanism will have a substantially longer efiicientlife.

Figures 6 to 11, inclusive, show certain alternative connections which may be employed to effect and control the operation of the compression rod 11 of the resistor. In Figures 6 and 7 the arm50 (corresponding to the arm 50) is mounted on a rock shaft 43* provided with a cam 44 for engagement with the tip 46 of the rod 11. In Figures 8' and 9 a rock shaft 43" is arranged along an axis at a right angle to the resistor and is provided with an arm 50 to which the link 58 is connected and with a cam arm 44 for 'engagement'with the tip 46 of the rod 11.

In Figures 10 and ll'the arm 50 to which the link 58 is connected is incorporated in a bell crank lever mounted on a supporting stud 43, the other arm 44 engaging the tip 46.

Safety of operation, from the standpoints of obtaining a slow starting speed and of preventing an overload on the motor, requires that the resistor 10 shall function to reduce the resistance in the motor circuit from maximum to minimum prior to the operation of the short circuiting switch and it is therefore indispensable that the truck shall be operated in the manner described.

The invention provides means for compelling such 0 eration, the means consisting of an interloc between the drum 16 of the reversing switch and the drum '19 of the short circuiting=switch whereby the drum 16 of the reversing switch cannot be moved from either of its operativepositions except when the short circuiting switch is fully opened and, preferably, the normal circuit of the resistor is broken, (thus making it necessary to bring the truck to a standstill and completely open the circuit of the motor before the reversing switch can be operated to change the direction of movement), and the .drum 19 of the short circuiting switch can-' not be moved to close said switch except when the drum 16 of the reversing switch is in either of its on positions, that is to ,say the-drum 19 cannot be operated to close the short circuiting switch when the reversing switch is in neutral position or prior to an actuation of saidreversing switch, In

the construction preferred the interlocking means for the

drums

16 and 19 includes a locking ball 71 which is confine d in and freely movable through .an opening 72 formed in" a supportingplate 73 interposed between the ends of the

drums

16 and 19,

the ball 71 being greater in diameter than the thickness-of said plate whereby it will always project from oneface of said plate or the other.- The drum 16 carries an end plate 74 which is formed with recesses 75 and 76 conforming to the ball 71 and arranged to co-operate with said ball in the lower and -upper positions, respectively, of said drum. The drum 19 carries an end plate 77 provided with a recess 78 conform- 9 extends k is held by the plate 77 in engagement in either of the recesses 75 or 76, accordingly as the reversing switch is set for forward or reverse direction of movement, said ball thus positively locking the drum 16 of the reversing switch in the position in which it was previously setby means of the handle.

35. This positive action of the ball 71 to lock the reversing switch drum 16 in either of its operative positions is maintained m long as the drum 19 is held out of its uppermost position bymeans of the pedal 41. However, when the pedal is released for the purpose of bringing the truck to a stop the drum 19 of the reversing switch is raised to its uppermost position in which the recess 78 alines with the ball 71 and at such time the locking action of said ball on the drum 16 is not maintained. Th-ereupon, with the truck at a standstill, the drum 16 of the reversing switch may be moved into new tral position or into the position toreversr the direction of movement of the truck, Assuming that the drum 16 is moved into neutral position the web 7 9 will act on the ball 71 and positively holdsaid ball engaged in the recess 78 so as to lock the drum 19 in its uppermost position. It follows that so long as the drum 16 is in neutral position the drum 19 of the short circuiting switch is positively locked in open position and can" not be moved from such positiona When however, the drum 16 is'set for the drive oi the truck in either direction the ball 71 wiii aline with either of the recesses 75 or 76, according to the position of the drum 1e and at such time the locking action ofthe n moved andv the short circuiting switch may be closed in the regular manner if so desired, the movement of the drum 19 from its up permost position being effective by means of the plate 77 to hold the ball 71 en aged in the recess 7 5 or 76, as the case may e.

It will be understood that the embodiment described is preferred, as now considered,-

but that the invention is susceptible of embodiment in modified forms and therefore poses of exposition.

that the specific description of the structural details as herein disclosed is not to be taken as imposing any limitations upon the appende claims or otherwise than for due pur-' with-said motor, switch and source, a short circuitingswitch in the circuit of the motor and main switch, a foot operated controlling element, and operative connections between said controlling element and said short circuiting" switch and resistance element whereby in either direction of its movement saidcontrolling element operates ment.

.ment, short circuiting 'whereby said controlling element as it is out 0 said resistance element progressively to increase or decrease the resistance and as it approaches or recedes from the limit of its movement in one direction closes or opens said short circuiting switch, the latter being closed bysaid controllingelement only when the resistance has been reduced to minimum.

2. In an industrial truck, in combination, an electric propelling motor,a source of ele trical energy, a reversing switch, a variable resistance element normally in circuit with said motor, switch and source, a short circuiting switch in the circuit of the motor and main switch, a brake for arresting the movement of the truck, a controlling element, and means operatively connecting said controlling" element to said resistance eleswitch and brake,

moved in one direction or the other operates said resistance element progressive to increase or decrease the resistance, as it approaches or recedes from the limit of its movement at which the resistance is maximum 'efiects the application or release of said brake, and as it approaches or recedes from the o posite limit of its movementv at which't e resistance is minimum closes or opens said short circuiting switch and cuts out or cuts i said resistance ele- 3. In an industrial truck, in combination, an electric propelling motor, a source of electrical ener a reversing switch, a variable resistor o the compression type normally in circuit with said motor, switch and source and having a movable part by which the resistor is regulated, a short circuitin switch operative to cut said resistor circuit, a brake for arrestin the movementof the truck, a foot operate controlling element, and means operatively connecting said controlling element to said movable part, short circuitingswitch and 1,ssc,asc

bra'ke whereby said element as it is moved in one direction or the other continuously crease the resistance, as it approaches or recedes from the limit of its movement at which the resistance is maximum efiects theance is minimum closes or opens the short circuiting'switch to cut out or cut in said resistor.

4. In an industrial truck, in combinatio an electric propelling motor, a source 0 electrical ener a reversing switch, a variable resistor o the compression type normally in circuit with said motor, switch and source, and having a movable part by which the resistance is regulated, a short circuiting switch operative to cut said resistor out of circuit, a pedal, an actuating element for operating said movable part, operative connections between said actuating element and said short circuiting switch and operative connections between sai pedalland said actuating element, whereby said pedal as it is moved in one direction or the other continuously operates said movable part' to increase or decrease --the resistance, and as it approaches or recedes from the limit of its movement at which,

the resistance is minimumclosesor opens the short circuiting switch to cut out or cut in said resistor. I

5. In an industrial truck, in combination 11 electric propelling motor, a source 0i electrical ener a reversing switch, a variable resistor o the compression type normally in circuit with said motor, switch and source, and having a movable part by which the resistance is regulated, a short circuiting switch operative to cut said resistor out of circuit, a pedal, an actuating element for operating said movable part, a link operatively connectingsaid actuating element and short circuiting switch, an upper lever, a lower lever, a link connecting said pedal and one arm of the @upper lever and one arm of the lowervlev'er and a link connecting .anotherarm of the lower lever and said actuatin element, whereby said pedal as it is move in one direction or the other continuously operates said movable part to increase or decrease the resistance, and as it approaches or recedes from the .limit of its movement at which the resistance is minimum closes-or opens the short circuiting switch to cut out or cut in said resistor.

6. In an industrial truck, in combination, an electric propelling motor, a source of electrical energy; a reversing switch, a variable resistor of t e compression type normally in circuit with said motor, switch and source, and having a movable part by which the re operates said movable part to increase or desistance is regulated, a short circuiting switch operative. to cut said resistor out of circuit, a brake for arresting the movement of the truck, a pedal, an actuating element for operatingsaid movable part, a link operatively connecting said actuating element 'and short circuiting switch, an upper lever,

. a lower lever, a link connecting the pedal and one arm of the upper lever, a link conneeting the other arm of the upper lever and one arm of the lower lever, a link connecting another arm of the lower lever and said actuating element, a lever for controlling the operation of said brake, and a link connecting-a third arm of-the lower lever and said brake controlling lever, whereby said pedal as it is moved in one direction or the other continuously operates said movable part to mcrease'or decrease the resistance, as it approaches or recedes from the limit of ts movement at whichthe resistance is maxisaid motor, switch and source, a short circuiting switch in the circuit of the motor and main switch, a brake for arresting the movement of the truck, a. foot operated controlling element, and means opera-tively connecting said controlling element to said resistance element short circuiting switch and brake whereby said controlling element as it is moved in onedirection or the other op- Herates said resistance element, progressively to increase or decrease the resistance as it approaches or recedes from the limit of-its movement at which the resistance is maximum effects the application or release of said brake, and as it approaches or recedes from the opposite limit of its movement at which the resistance is minimum closes or opens said short circuiting switch and cuts out or cuts in said resistance element.

8. In an industrial truck, in combination,

- an electric propelling motor, a source of electrical energy, a reversing switch, a variable resistance element normally in circuit with said motor, switch and source, said element being operative to vary the speed of said motor in normal running, a foot-operated'controlling element, and operativebonnections between said controlling element and resistance element whereby in either direction of its movement said controlling element operates said resistance element progressively to increase or decrease the resistance.

9. In an industrial truck, in combination, an electric propellingmotor, a source of *variable resistance element normally electrical energy, a reversing switch, a vari-' able resistance element normally in circuit with said motor, switch and source, a brake for arresting the movement of the truck, a controlling element, and means operatively. connecting said controlling element to said resistance element and brake, whereby said controlling element as it is moved in one direction or the other operatessaid resistance element progressively to increase or decrease the resistance andfasit approaches or recedes from the limit of its movement at which the resistance is maximum, effects the application or release of said brake.

10. In an industrial truck in combination, an.elect ric propelling motor, a source of electrical energy, 'a reversing switch, a in circuit with said motor, switch and source, a brake for arresting the movement of the truck, a foot operated controlling element and means operatively connecting said controlling element to said resistance element and brake, whereby said controlling element as it is moved in one direction or the other operates said resistance element progres 'sively to increase or decrease the resistance and as it approaches or recedes from the limit of its movement at which the resistance is maximum effects the application or release of thesaid brake.

11. In an industrial truck, in combination, an electric propelling motor, a source of electrical energy, a reversing switch, a variable resistance element normally in circuit with said motor, switch and source, a short cirinc cuiting switch in the .circuit of said motor and reversing switch, the latter having two extreme operative'positions and an intermediate neutral position, a controlling element operatively connected to said resistance element and short circuiting switch, and means co-operating with said reversing switch and short circuiting switch whereby the short circuiting switch except in a definite open position locks the reversing switch in either of its extreme positions and the reversing switch when in neutral position locks the short circuiting switch in said open position, the controlling element as it is moved in one direction or the other operating said resistance element to increase or decrease the resistance and as it approaches or recedes from the limit of its movement at which the resistance has been reduced to minimum closes or opens the short circuiting switch.

12. In an industrial truck, in combination, an electric propelling motor, a source of electrical energy, a. reversing switch, anva'riable resistance element normally in circuit with said motor, switch and source, a short circuiting switch in the circuit of said motor V in circuit with said motor, switch an trolling element operatively connected- -to said resistance element and short circuitin switch, and means cooperating with sai reversing switch and short" circuiting switch whereby the short circuiting switch except in a definite open position locks the reversing switch in either of its extreme positions and the reversing switch when in neutral position locks the short circuiting switch in said open position, the controlling element as it is moved in one direction or the other operating said resistance element to increase or decrease the resistance and as it appreaches or recedes from the limit of its movement at which the resistance has been reduced to minimum closes or opens the short circuitin switch.

'13. In an in ustrial truck, in combination,

an electric propelling-motor, a source of electrical energy, a reversing switch, a variable resistance of the compression type nprmally source,

( and having a movable part by which the resistance is regulated, a short circuiting switch operative to out said resistor out of circuit, an operativeconnection between the short circuiting switch and said movable part, the reversing switch having two extreme operative positions and an intermediate neutral pos1tion,'a foot operated controlling element operatively connected to said movable part, and means co-operating. with said reversing switch and short circuit ing switch whereby the short circuiting switch except in a definite open position locks the reversing switch in either of its extreme positions and the reversing switch when in neutral position locks the short circuiting switch in said-open position, the controlling element as it is moved in one direction or the other operating said resistor to increase or decrease the resistance'and as it approaches or recedes from the limit of its .movement at which the resistance has been reduced to minimum closes on opens the short circuiting switch.

14. In an industrial truck, 'in combination, an electric propelling motor, a source of electrical ener a reversing switch, a variable resistance lement normallytin 'circuit with said motor, switch andsource, a short cir- -:cuiting switch in the circuit-of said motor and reversing switch,the latter having two extreme positions and an intermediate neutral position, and means-co-operating with said reversing switch andshort circuiting I ,switch whereby the short circuitinl'gswitch .except in a definiteo en position ocks the reversing switch in (it er offits extreme po sitions and" the reversingswitch when in neutral 'position locks the short circuiting I switch in-said open position. t

15. In an industrial truck,incombination, an electric propelling motor, ajsou'rce of electrical energy, a reversing switch, u. variable,

resistance element normally in circuit with sald motor, switch and source, a short circuiting switch in the circuit of said motor ment having a movable part by which the resistance is re lated, an operative connection between said movable part and said short circuitin switch, and means co-operating with sai reversing switch and short circuiting switch whereby the short circuiting switch except in a definite open position locks the reversing switch in either of its extreme positions and the reversin when in neutral position locks the s ort circuitin r switch in said open position.

16. In an industrial truck, in combination, an electric propelling motor, a source of electrical ener a reversing switch, a variable resistance e ement normally in circuit with said motor, switch and source, a short circuiting switch in the circuit of said motor and reversing switch, the latter having two extreme positions and an intermediate neutral position,"means co-operatin with'said reversing switch and short circuiting switch whereby the short circuiting switch except in a definite open position locks the reversingswitch in either of its extreme positions and the reversing switch when in neutral position locks the short circuiting switch in said open position, and a pedal constituting a common operating element for said variable resistance element and said short circuiting switch and whereby said pe al as it is moved in one direction or the other operates said resistance element to increase or decrease the resistance vand as it approaches or recedes from the switch operatively connected thereto limit of its movement at which the resistance ing the drum of the short circuiting switch,

in connection with the operation of said movable part whereby the'short circuiting switch is closed when the resistance is reducedto minimum, the drum of the reversing switch having two extreme operative positions andan intermediate neutral, position, and means co,-operatin with said whereby the short circuiting switch neutral position locks the short circuiting switch in said open position.

18. In an industrial truck, in combination, an electric propelling motor, a source a of electrical energy, a reversing switch, a

variable resistance element normally in circuit with said motor, switch and source, a

' short circuiting switch in the circuit of said motor and reversing switch, the latter having two extreme operative positions and an intermediate neutral position, and means for preventing an 'operation'of the short circuiting switch when the reversing switch is in neutral position and for preventing an operation of the reversing switch from either of its extreme positions except in a definite open position of the short circuiting switch.

19. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a main switch, a variable resistance element normally in circuit with said motor, switch and source, a short circuiting switch in thecircuit of the motor and main switch the'short circuiting switch having a movable element and a controlling element operatively connected to said resistance element and positively connected to the movable element of the short circuiting switch and actuated by the truck operator,

'-' the main switch beingiclosed throughout the operation of the true 20. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a main switch, a variable resistor of, the compression type normally in circuit with said motor, switch and source,

a short circuiting switch in the circuit of the motor and main switch, the short circuiting switch having a' movable element and a controlling element operatively connected to said resistance element and. positively connected to the movableelement of the short circuiting switch and actuated by the truck operator, the main switch being closed throughout the operationof the truck.

21. In an industrial truck in combination an electrical propelling motor, a source 0 electrical energy, a variable resistance element normally in c rcuit with said motor and source, a short circuiting switch in the circuit of said motor andsource, a foot operated controlling element, and o erative connections between said control ing element and said short circuiting switch and resist ance element'whereby in either direction of its movement said controlling element operates said resistance element progressively to increase or decrease the resistance and as it approaches or recedes from the limit of its movement in one direction closes or opens said short circuiting switch, the latter being closed by saidcontrolling element only when the resistance has been reduced to minimum.

22. In an industrial truck, in combination an electrical propelling motor, a source oi electrical energy, a variable resistance ele-.

by in either direction of its movement said N controlling element operates said resistance element. progressively to increase or decrease the resistance and as it approaches or re- ,cedes from the limit of its movement in one direction closes or opens said short circuiting switch, the latter being closed by said controlling element only when the resistance has been reduced to minimum.

23. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a variable resistance element of the compression type normally in circuit with said motor and source, said element beingfoperative' to vary the speed of said motor in normal running, a spring held foot operated controlling element, and operative connections between said controlling element and said resistance element.

24. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a variable resistance element normally in circuit with said motor and source, a brake, a foot operated controlling element, and operative connections between said controlling element and said resistance element and brake.

. 25. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a variable resistance element normally in circuit with said motor and source, a brake, a controlling element actuated by the operator and operative connections between said controlling element and-said resistance element and brake.

'matically preventing an actuation 'of said switch to open the same at any period of the movement of said controlling element beyond its initial position.

27 In anindustrial truck, in combination, an electrical propelling motor, a source of electrical energy, a main switch, a. variable resistance element normally in circuit with said motor, switch and source, a fdot operated controlling element, operatlve connections between said controlling" element and said resistance element, and means for automaticall preventing an actuation of said controlling element while. the main switch is open.

28. In an industrial truck, in combination an electrical propelling motor, a source oi electrical energy, a main switch, a variable resistance element normally in circuit with saidmotor, switch and source, a foot operated controlling element, operative cbnnections between said controlling element and sald resistance element, and means for automatically preventing an actuation of said resistance element normally in circuit with said motor, switch'and source, a controlling 'elernent,'operative connections between said controlling element and said resistance element and means for automatically preventing an actuation of said main switch'to open the sameat any riod -of the'movement of said controlling 'element beyond its initial position. i

30. In an industrial truck, in combination, an electrical propelling motor, a source of electrical energy, a mam switch, a' variable resistance element normally in circuit with said motor, switch and source, a controlling element, operative connections between said controlling element and said resistance element and means for automatically preventing an actuation of said controlling element while the main switch is open.

31. In an industrial truck, in combination,'

an electrical propelling motor, a source of electrical energy,-a main switch, a variable resistance element normally in circuit with said motor, switch and source, a controlling element, operative connections between said controlling element and said resistance element and means for automatically preventingan. actuation of said main switch to open the same at any. period of the movement of said controlling element be ond its initial position and for automatic ly preventing an actuation of said controlling element while the main switch is open. v

I testimony whereof I afiix m signature.

. WILLIAM CARR.