US2774437A

US2774437A - Overload responsive switch mechanism for industrial elevating truck

Info

Publication number: US2774437A
Application number: US354524A
Authority: US
Inventors: Edward H Remde
Original assignee: Baker Raulang Co
Current assignee: Baker Raulang Co
Priority date: 1953-05-12
Filing date: 1953-05-12
Publication date: 1956-12-18
Anticipated expiration: 1973-12-18

Description

Dec. 18, 1956 E. H. REMDE 21,77 7

OVERLUAD RESPONSIVE SWITCH MECHANISM FOR INDUSTRIAL ELEVATING TRUCK Filed May 12, 1953 5 Sheets-Sheet l INVENTOR.

- I [OW/W0 #Aewos 1f ATTORNEY Dec, 18, 1956 E. H.

REMDE

2,7

OVERLOAD RESPONSIVE SWITCH MECHANISM FOR INDUSTRIAL ELEVATING TRUCK Filed May 12, 1953 5 Sheets-Sheet 3 INVENTOR. 0 WARD A Qt-MOE ATTORNEY Dec. 18, 1956 E. H. REMDE 2,774,437

OVERLOAD RESPONSIVE SWITCH MECHANISM FOR INDUSTRIAL ELEVATING TRUCK Filed May 12, 1953 s Sheets-Sheet 4 PUMA More l 7/47- #0/57' Courswim falvey United States Patent OVERLOAD RESPONSIVE SWITCH IVIECHANISM FOR INDUSTRIAL ELEVATING TRUCK Edward H. Remde, Cleveland, Ohio, assignor, by mesne assignments, to The Baker-Raulang Company, a corporation of Delaware Application May 12, 1953, Serial No. 354,524

Claims. Cl. 180-82) This invention relates to a vehicle for transporting loads having incorporated therein means adapted to be actuated when an overload is positioned on or engaged by the load carrier of the vehicle, whereby the power means for one or more operating mechanisms are made inoperative the eflfect of which is to prevent operation of the vehicle and/or a mechanism thereon until the overloading condition is remedied; by preventing overloading of the vehicle undue wear on and/ or danger of breakdown thereof are reduced. Where the vehicle is provided with a vertically movable load carrying member, the latter may be operated to transport (a) loads consisting of bulk materials in bags, bales, rolls of paper and the like and (b) pick up and transport loads mounted on skids, dunnage and pallets. In the preferred application of the invention it is incorporated in a vehicle the overloading of which effects a tilting of the vehicle chassis about the wheel axle at one end thereof; in one form of vehicle construction referred to the load supporting member or carrier is suspended by means which are operable to raise and lower the member or carrier, whereas in another form of vehicle construction the load carrying member extends beyond the truck supporting wheels at one end of the truck frame. In the preferred form of construction the load supporting member or carrier is slidably supported on the truck chassis for vertical movement, for example, as in a truck of industrial elevating type, as shown herein, wherein the load carrier extends beyond the truck wheels at one end of the truck frame, and is supported on an elevating member which is raised and lowered on vertical guides supported on the truck frame. In trucks of this type, the weight of the end portion of the truck chassis remote from the load carrier and of all equipment mounted on such portion serves as a counter-weight for the load which may be positioned on the load carrier. As the load carrier extends outwardly at one end of the chassis beyond the adjacent truck supporting wheels, it will be seen that the axis on which these wheels rotate forms a fulcrum between the load carrier and the remote end portion of the chassis, so that the weight of such end portion and all equipment thereon on the adjacent side of the fulcrum determines the carrying capacity of the truck, since any overload on the load carrier exceeding the weight at the opposite or remote end of the chassis will cause the latter to tilt about its fulcrum.

While industrial trucks of this latter type are designed to carry loads having a predetermined carrying capacity as to weight, the truck driver is often induced, for sake of expediency or otherwise to overload the elevatable load carrier beyond the rated capacity of the truck. Such overloading obviously effects undue wear on various parts of the truck, resulting in a shorter life thereof or in causing repairs and breakdowns of the truck, whereby the expense of keeping the truck in service is increased. 7 In the form of construction shown, and as later set forth, any loading of the carrier with a load in excess of the rated carrying capacity of the truck has the effect 2,774,437 Eatented Dec. 18, 1956 of making one or more operated mechanisms of the truck inoperative, whereby the truck driver at once becomes aware of the overloading condition, so that it can be promptly rectified. The mechanism or mechanisms to be made ineffective or inoperative depend upon the electrical circuit connections and the controlling switch therein, as later set forth.

One object of the invention is to provide an improved mechanism for automatically making an operating mecha nism of a truck inoperative when a load, which exceeds the rated capacity of the truck, is placed on its load carrying support, whereby strains and/or breakdowns and undue wear on the truck, are eliminated.

Another object of the invention is to provide an improved load limiting mechanism inter-related to the raising means for the elevating member of a truck for preventing raising of the elevating member following the engagement of the load carrier with an overload but permitting the elevating member to be lowered, whereby the load carrier may be lowered, if necessary, and the load reduced or removed.

Another object of the invention is to provide, in a truck, an improved load limit mechanism of simple construction and capable of quickly responding to any attempt to place on the load carrier of a truck or raise a load which exceeds the capacity of the truck.

Another object of the invention is to provide, in a truck wherein the load carrier thereon extends outwardly beyond the wheels at one end of the chassis and the wheels at the opposite end of the chassis are mounted on an axle having forwardly and rearwardly extending members the outer ends of which are mounted on resilient supports on the chassis, improved means controlled by the movementof the chassis relative to one of said supports, due to an overload on the load carrier, for making one or more operating mechanisms on the truck inoperative.

Another object of the invention is to provide, in an elevating type of truck, the axle for one pair of supporting wheels at one end of the truck chassis having alined forwardly and rearwardly extending members the outer ends of which are mounted in resilient seats fixedly supported on the chassis and arranged to be compressed when the chassis is tilted, and the opposite end of the chassis is provided with a load carrier, improved load limiting mechanism adapted to make one or more mechanisms on the truck inoperative, due to tilting of the chassis when an overload is positioned on or engaged by p the carrier.

Another object of the invention is to provide an im one or more mechanisms of a truck inoperative when a load exceeding a predetermined capacity thereof is placed on the truck carrier or engaged thereby preliminary to raising of the load, the mechanism including means arranged, during travel of the truck in transporting a load within the capacity of the truck, to make the load limiting mechanism ineffective during traverse of the truck wheels over rough surfaces.

A further object of the invention consists incertain improvements in the form of construction shown in my co-pending application filed February 8, 1950, Ser. No. 143,064.

Other objects of the invention will be apparent to those skilled in the art to which my invention relates from the following description taken in connection with the accompanying drawings, wherein Fig. 1 is a side elevation of an elevating truck embodying my invention, parts being broken away;

Fig.2 is a section on the line 2--2 of Fig. 3;

Fig. 3 is a section on the line 3-3 of Fig. 2, parts being broken away;

' such as a wheel. 'rear wheels 4 may be driven and either the front or rear, wheels may be mounted to effect steering of the truck. 7

thereof With lateral extensions, as shown at 6a.

Fig. 4 is a fragmentary sectionon the line 4-4 of Fig.2; a 'Fig. 4a is an enlarged view taken approximately along line" int--41: of Fig. 4; V

5 is a section similar to Fig. 4, but showing the I position of the parts when the truck carrier is overloaded;

Fig. 6 is a fragmentary section on the line 6-6 of 'Fig. 5;

7 is a diagram 'of the circuits;

Flgs. 8 and 9 are diagrams of modified circuits;

Fig. 10 is a section similar to Fig. 3, but showing a inlod fie'd form of construction, on the line 10-14) of Fig. Fig. 11 is a section on the line 11-11 of Fig.10; and

12, is a diagram showing a modified circuit.

In the drawings, referring to Figs. 1 to 7, inclusive, 1

indicates as an entirety a truck comprising a frame or endon a pair of wheels 3 chassis 2' mounted at its front and at its rear end on wheels 4. In the disclosed form of construction (a) the wheels 3 are drivenby a suitable driving mechanism having a power supply unit mounted on the rear end portion of the chassis 2 and enclosed in a casing 5; and (b) the wheels 4 are dirigibly mounted on the opposite ends of the axle member indicated as an entirety at 6 for steering'by a manually operable device, However, where found desirable, the

In the present disclosure, the wheels 4 are dirigibly mounted in a well known manner on the opposite ends of the axle 6, which in turn is mounted on the chassis 2 for swinging movement in a plane transverse to the.

D V 6 consists of the followindicate :almed supporting members, respecpreferably integral with the axle 6, disposed intermediate the ends thereof and extending forwardly 'and' rearwardly of the axle '6. substantially in the plane thereof. 1

are provided with collars 14x The member 14,1411, (preferably integral therewith) and the end portions 6a of the members, outwardly of the collars 14x, are mounted in supports 15, 15x, the "support 15 .for the member 14 being secured to a transversely extending 'suspension' member 15 (later referred to) and the support 15x for the member 14a being fixedly mounted on a transverse wall 11) forming part of the chassis 2. The support 15x consists of an inverted U-shaped wall 15a the sides of which'terminate 'at their lower ends in out- "turned flanges 15b suitably secured by bolts 15c to a bottom plate 15a. The inner edges of the walllSa are suitably secured to the adjacent chassis 'wall 1b, which,

with the walls 15a and plate 15d, form a casing for a' resilient seat member 15s for the end portion 6a of the adjacent axle supporting member 14a. The seat member 15c is formed substantially centrally thereof with an in- .wardly extending opening 15c (see Fig. 3) forming a axis of the chassis, when either wheel 4 rides transverse chassis wall 10.

axle supporting member 14 in theadjacent seat member 15c, except that (a) thew/all 15a is not fixed to the chassis wall 1:: and (b) the bottom plate 15d of the adjacent casing for the seat member 152 is suitably secured at. its opposite end portions to a transverse plate or suspension 15', the latter having extensions 16, which extend beyond the opposite sides'cf the adjacent support 15, and are adapted to benormally engaged by, spaced abutments 16x (later referred to) suitably fixed to the The seat members 152, are shaped so as to position the seats 1'52 therein, whenthe axle 6 is in normal position, co-axially with the central longitudinal axis of the chassis. The walls of each seat 7 7 member 15e are preferably formed of a compressible material having elastic or resilient characteristics, such as rubber or rubber compound, and have a length substantially equal to thewidth'of the casing therefor and the exterior contour of these walls approximate the shape of the latter, but are initially somewhat larger than the area Within and defined by the walls 15:: and the plate 15d secured thereto, so that when each compressible seat member is initially positioned in thc'adjacent casing walls 15a its lower portion extends below the flangeslSb thereon. Accordingly, when the plate 15d isclamped in 'position by the bolts 15c, the material forming the walls of the seat member is compressed between the inner surfaces of the inverted wall 15a, the pla'te'15d and exterior surfaces of the adjacent extension 6a and also expanded outwardly into engagement with the adjacent collar 14x to form a cushion between the adjacent axle supporting member and the outer edges of the wall 15a to absorb stresses endwise outwardly on the adjacent supporting member. As the compressible resilient material of the seat members engages under pressure. with the entire outer surfaces of the end portions 611 and such pressure is substantially equal radially inwardly on these.

surfaces, the endportions 6a are supported and yieldably maintained in normal position during truck travel over substantially smooth road surfaces. However, when one wheel rides an'obstruction or a depression in the road surface, the axle 6 bodily swings substantially vertically relatively to the other wheel, but as the end portions 6a are fixed to the axle and non-rotatively fixed to'the walls seatinto which adjacent end portion 6a extends. Each' of the end portions 6a is provided on diametrical sides y preference, the extensions on the end portions 6a are provided by making the latter of substantially elliptical-shape in cross section, as shown in Figs. 4 and 5 and the seats 152' are of complementary shape in cross section to prevent rotation of the end'portions 6a therein. The support 15 is similar in construction to the support 151 to nonrotatably support the end portion 6a of the adjacent of the seats 15c, as already set forth, the compressible material Willyield to the pressure applied at diametrical sides of the extensions 6a to compensate for the movement of the axle, and after the wheel has traversed the uneven surface, the compressed portions of. the material will serve to center the end portions 6a into normal position. The axle and mountings 13 therefor, consisting of the members 14, 14a, and supports 15, 15x, for the latter, 7

constitute the'subjechmatter disclosed and claimed in the co-pending application filed by Robert H. Davies, Ser. No.

51 3,655; accordingly, no claim thereto is made herein.

"mechanismwhich includes a motor 7 (see Fig; 7) in the;

'circuit 7x and operatedby the controller 7a preferably connected by a linkage to anac-celerator pedal 7 b, the cir- The travel of the truck is effected by a suitable driving cuitbeing connected to batteries enclosed in the casing 5. As shown'in Fig. 1, the linkage for the pedal 7b is. connected' to and rotates a shaft '7c, which is suitably ,con-

nacted by gearing to the controller 7a to rotate the latter. .The shaft 7c is provided with a cam 7d, which,iin the neutral position of the controller, engages a. spring biased plunger 72 to maintain the switch open, but upon rotation of the shaft 70 relieves pressure on the plunger, whereby the switch closes, as later set forth. iReferi-ing to Fig. 7 7 indicates a separate normally open. switch in =2. lead 7" of the motor circuit 7xadapted to prevent operation of the motor, so that'operation ofthe controller 711 is ineffective. The switch 7'; is positioned below a hinged seat 8 for thedriver. The seat 8 is biased upwardly by a spring 8:5, as shown in'full lines in Fig; .1,

in which position the switch 7 is open; butlwhenthe driver occupies the seat .8, his weight overcomes the tension of the spring 812,. so: that the seat swings down wardly and closes the switch 7, thereby closing the circuit in lead 7 I -Where the construction of the chassis provides for truck operation with the driver in astanding position on a platform, a portion of the latter consists of a hinged, upwardly biased member (as shown in my co-pending application Ser. No. 143,064) on which the driver stands to close the normally open switch 7 7x indicates a service brake pedal which is biased in one direction by a spring (not shown). The pedal 7x is connected by a linkage 7x" to a brake (not shown). By operation of the accelerator pedal 7b forward travel of the truck at different speeds is effected through fingers 1', 2', 3, etc.; whereas rearward travel at different speeds is effected through the same fingers, except that fingers 4' and 5 are interchanged by operation of a lever connected to linkage 9a.

Thefront end of the chassis 2 is provided with trunnions 10 (one being shown in dotted lines-see Fig. 1) on which a pair of plates 10a, only one of which appears in the drawing, are tiltably supported. The plates 10:: are suitably fixed to outer guide channels 11 which slidably support inner guide channels 11a. The lower ends of the guides 11 are connected together by a base 10b and thereabove by a plate 100, whereas the upper ends of the guides 11a are connected together by a member (not shown). 12 indicates as an entirety an elevating member supporting a carrier or load support 12a. The carrier 12a is shown as consisting of a pair of forks 12b adapted to be projected into a pallet whereby a load on the latter may be raised. The elevating member 12 is raised relative to the guides and the guides 11a are operated endwise upwardly relative to the guides 11 by an hydraulically operated mechanism preferably similar to that shown in Letters Patent No. 2,598,566 to Max Lehmann. As the hydraulically operated mechanism, the elevating member and load carrier and guides for the elevating member are mounted on the plates 10a and the latter are trunnioned at 10 on the chassis 2, as already described, the assembly may be tilted by operation of a mechanism 12x, preferably of the hydraulically operated type as shown in Letters Patent No. 2,471,429 to P. E. Hawkins and operated by a suitable lever (not shown). The raising mechanism and tilting mechanism are operated by fluid (such asoil) under pressure supplied thereto by operation of a pump, the latter being driven by a motor 17, connected in an electric circuit 17a, the liquid supply to these mechanisms being controlled by suitable levers (not shown) operatively connected to suitable valves (not shown). driven only when pressure in the system is required to raise the elevating member 12 or to tilt the plates 10:: and parts mounted thereon. In this arrangement, the levers are suitably connected to a switch KB, connected in the circuit 17a, so that when either one of the levers is operated it operates the switch to close the circuit 17a, whereby the motor 17 is set in operation to drive the pump and thus supply pressure to swing the elevating mechanism about the trunnions 10 or raise the elevating member 12 dependent upon which lever is operated.

The abutments 16x are disposed at opposite sides of the support 15 and each consists of a horizontally disposed bar 18 the inner end of which is provided with a downwardly extending element 18a, and a pair of spaced, downwardly extending legs 18b, which engage the adjacent extension 16 on the member 15'. The bars 18, elements 18:: and legs 18]) are suitably secured (preferably welded) to the wall 16, so that the abutments 16x co-operate with the support 15x to support the adjacent end of the chassis on the axle 6 as shown in Figs. 1, 2 and 4. As shown, the elements 18a are in close relation to the side walls of the adjacent wall 15a to preventlateral movement of the support 15, but are free 'to slide relative to these side walls when the chassis is tilted, as shown in dotted lines in Fig. 1, dueto an By preference, the motor 17 is overload on the carrier 12a, as later set forth. As the abutments 16x are disposed at opposite sides of the support 15 and engage the extensions 16, and the elements 18:; are in close relation to the sides of the support 15 the latter is held against displacement and/or from turning during swinging movement of the axle 6.

The abutments 16x and member 15 are connected together by devices which serve to maintain them in associated relation and to adjustably limit the upward movement of the abutments relative to the support 15. These connecting devices consist of bolts 18:: each extending through alined openings in one of the bars 18 and the adjacent extension 16, the bolt extending beyond the latter and provided with screw threads for a nut 18a. As shown, the nuts 18d are spaced from the bottom walls of the extensions 16 and serve to limit the upward movement of the abutments relative to the support 15. As will be observed, this relative movement can be adjusted by turning the nuts 18d on the bolts 180. 18s indicates springs coiled around the bolts 18c and interposed between the bars 18 and extensions 16. As shown in Fig. 4, when the abutments 16x are seated on the extensions 16 the springs 182 are compressed and when the abutments 16x move upwardly, due to tilting of the chassis 2, the springs 18e prevent the support 15 from moving upwardly therewith due to any frictional engagement between the elements 18a and sides of the adjacent wall 15a.

19 indicates as an entirety the load limiting mechanism adapted, when operated, to make the operation of the

motors

7 and 17 inefiective, so that the truck cannot be driven, the tilting mechanism 12x for the guides 11 can not be operated and the mechanism for raising the elevating member 12 cannot be operated to raise the latter; however, when the elevating member 12 is in a raised position, it may be lowered as the member gravitates downwardly when the adjacent valve is operated to release the fluid pressure therefor. The mechanism 19 consists of the following: 19a indicates a normally closed switch in the lead 7" of the circuit 7x. The switch 19a is mounted on a bracket 20 fixed to the wall 10, the switch contacts being enclosed in a casing 20a and adapted to be engaged or disengaged by operation of a plunger 21 (formed of non-magnetic material) slidably fitting and extending through a tube 19' fixedly mounted in an opening formed in the laterally extending leg of the bracket 2%) (see Fig. 4a). The plunger 21 is normally biased outwardly by a spring (not shown) in the casing 20a. 21a indicates a resilient metallic strip suitably mounted on the bracket 20 inwardly of the plunger 21 and extending outwardly in alinement with the latter for engagement with and disengagement from a rest 22, which is mounted on the top of the adjacent wall 15a (see Fig. 6). When the carrier 12a is not provided with a load or a load thereon is within the rated capacity of the truck, the spring strip, being in engagement with the rest 22, is biased upwardly and supports the plunger 21 in retracted position (see Figs. 1, 2 and 4) in which position the switch 19a is closed as shown in Fig. 7. If an overload is placed on the carrier 12a or the latter engages an overload preliminary to raising it, the chassis is tilted about the axle for the wheels 3 (see dotted lines in Fig. 1), thereby moving the abutments 16x to the position shown in Figs. 5 and 6 and disengaging the strip 21a from the rest 22 and allowing the strip to fiex downwardly, thereby relieving pressure on the plunger 21 and permitting the latter to move endwise outwardly. The outward movement of the plunger serves to open the switch to control the circuits as later set forth. The rest 22 consists of an elongated member (preferably a bolt) screw threaded into an opening formed in a lug 22a suitably fixed to the top of the adjacent wall 15a. By adjusting the rest 22 relative to the lug 22a, the opening of the switch 19a can'be controlled to meet specific conditions; for example, where capacity of the truck. e

7,- it is desired to transport loads in excess of the rated Operation: Ifthe truck'is at rest and its driver not in driving position, relay coils of KA and KB in leads 26, 27, are derenergized, tilt-hoist switch K is open, accelerator operating switch 70 is open, the overload or pres-.

sure switch 19a is closed, the seat operated switch 7' ,is open, switches KA' and KA", which are closed by relay KA are open, switch KA which is operated by relay KA is closed, and switch KB, which is closed by relay KB, is open. 7 If driver occupies seat 8, switch 7" is closed. ;Next, the driver operates accelerator pedal 7b to close the circuit 7x between the controller and motor 7., If the controller 7a is moved to finger 1' position relay coil KA is energized, switches KA' and KA" are closed,

switch KA is opened and current is supplied to motor.

7 to eifect travel of the truck; if the controller is moved ;to finger 2 position or succeeding finger positions; finger .1 is cut out so that the controller cannot be reversed to a'lower speed position and then moved to a high speed position without first moving it to finger 1 position.

To'tilt the elevating mechanism about the trunnions lowered position, the truck is driven forward to project' the forks 12b into the pallet; next, the lever is operated to close switch Kwhereby switch KB will be closed by relay KB, the motor 17 will drive the pumpand the valve connected with the adjacent'lever willbe opened to supply liquid under pressure to the cylinder and raise the elevating member, whereby the forks 12b will engage the pallet and raise it and the load thereon. However,

if the load exceeds the rated carrying capacity of the truck (or such'lirnit as may be set by the adjustment of the rest 22 to permit a predetermined movement of the 'abutments 16x), the load will react on the forks and effect a tilting of the chassis 2 as shown in Figs. 1, and 6,

where it will be noted that the abutments have moved;

upwardly relative to the member 15' and opened switch 19a. It will thus be seen that upon opening of switch 19a, coils of relays KA and KB are de-energized and switches KA',-KA'f and KB. are opened to cut oil the supply of current to

motors

7 and 17 and thereby prevent. raising of the elevating member, tilting of the mechanism and truck travel. This inoperative condition will continue until the load is removed from the forks 12b or the load is reduced to or below the load limit.

26at a point outwardly of the switch 19a, so that in the 7 above the adjacent. casing 32 indicates a support pivotally mounted at its upper-end adjacent the upper end event of an overload on the carrier and operation of V switchl9a, switches KA? and KA are opened to cut oil supply of current to motor 7, but switch KB remains 7 closed to permit operation of motor 17.

Fig. 9 shows another modified circuit, similar to the circuit shown in Fig. 8, except that the switch 19a is connectedin a lead 26 in which a time delay coil 28 is connected for controlling a normally closed switch 28a, whereby the circuits to

motors

7 and 17 are maintained closed for a limited time period, to take care of a momentarily upward movement of the abutments 16x relative to the member and prevent opening of switch 19a resultingi rom rough surface conditions during truck travel.

Fi'gSflO and 11 illustrate a modified form of construction wherein thev outer end portions 6a of the axle supporting members .14, 14a. are non-rotatably mounted in.

casings 30, 30a, but the latter are suitably fixed (preferably welded) to the walls 1b, 10, respectively, of the chassis 2; in this arrangement, when an overload is PbSif tinned on the carrier the resilient seat members 29 permit relative movement between the chassis 2' and supporting members 14, 14a, due to tilting of the chassis about I struction shown in Figs. 1 to 6, by employing a multiplying leverage system, indicated as an entirety at 31,. the switch 19a is readily controlled. The system 31 consists of the followingz 3la indicates a bracket suitably fixed to the inner side of the chassiswall 1b and disposed of the bracket 31a and depending downwardly and adapted to'be adjustably related to the wall 1b by a screw 32a for apurpose later set forth. 33 indicates a housing fixed to support 32 and' enclosing the normally closed switch. 1911 which is controlled by an outwardly.

spring biased plunger 33a toclose and open the circuit for the switch. 34 indicates a resilient metallic strip'suitably fixed to 'the top wall of the housing 33 inwardly of the plunger 33a and. extending outwardly in alinement with and engaging the latter for holding the plunger inwardly, as later set forth, whereby the eircuit'for the switch is .closed.' 35 indicates an elongated lever the inner end of which is pivotally mounted at 35a' on a bracket 35a suitably fixed to the inner side of the chassis wall 10. The outer endportion of the lever 35 engages the outer end portion of the resilient strip 34 and operates to maintain the strip under spring tension in a predetermined position, whereby the plunger 33a is maintained in switch closing position. an adjustable fulcrum for the lever 35 consisting of the following: 36a, 3612, indicate upper and lower endwise V 7 related, members, the inner ends of which are adjustably connected together for a purpose later setforth, the lower end of the member 3617 being pivotally seated on the bottom wall of an inwardly extending recess 37 formed in the axle supporting member 14. The recess 37 is enlarged to permit swinging movement of the members 36a, 36b; 7. The upper end of the member 36a is pivotally connected to the lever35. A spring 38, which is suitably anchored at its opposite ends to the member 14 and lever 35 between the fulcrum 36 and strip 34, serves to bias the lever 35 downwardly andco-operates with'the bracket 35a to maintain the member36b in its seat in the recess 37. As will be observed, when the chassis is tilted about the axle for the wheels 3, the rear end portion of the chassis 2 and supporting members 14,

14a, move upwardly, the endportions 6a of the latter in:v

be obs'erved that the fulcrum 36 for the lever 35 is 10- cated close relation to the pivot 35a{ for the latter to'insure an adequate range of movement of the outer end of. the lever. As the relative movement between the chassis and the axle'supporting members 14, 14a, incident to overloading conditions, is limited, I'providese'parate. correlated adjustment means for the switch housing 33 and fulcrum on which the lever 35 rocks, whereby; with :the chassis 2 in normal position, the strip 34 is main-,

tainedby the lever 35 in a. predetermined.relationto the switchplunger 33a,qso that thelatter may beefiective to open the switch 19a upon rocking movement of the,

36 indicates as an entirety 9 lever 35. One of the adjusting means consists of the screw 32a (already referred to) the adjustment of which positions the support 32 relative to the chassis wall 1b, the support 32 being fixed to the bracket 31a in adjusted position by a screw 32a extending through an elongated arcuate slot 32x and threaded into an opening formed in the bracket 31a, such adjustment serving to raise or lower the switch housing 33 and support the latter in the desired position. The adjusting means 36x between the fulcrum members 36a, 36b, serve to increase or decrease the length of the fulcrum 36, whereby the latter co-operates with the pivot 35a to support the lever 35 in that position wherein its outer end, through its engagement with the resilient strip 34, maintains the switch plunger 33a in switch closed position.

The adjustment means 36x preferably consist in enlarging the upper end of the member 36b and forming therein an inwardly extending screw threaded opening 39 and providing screw threads on the inner end portion of the member 36a for adjustable engagement with the screw threads in the opening 39, as shown in Fig. 11. The members 36a, 36b, are secured together in adjusted position by a nut 40 threaded on the member 36a and a lock nut 40a.

Fig. 12 is a diagram showing a modified circuit for the travel motor, switch controls for the chassis tilting mechanism and raising mechanism for the elevating member, and wherein the normally closed switch 190 is ineffective where, during travel of the truck in transporting a load within the rated capacity thereof, the wheels 3 traverse rough surfaces and cause a bumping of the load. In this view, the motor 7 is connected in the circuit 41 controlled by the controller 7a. The circuit 41 includes a lead 42 having branches 42a, 42b, and branch 42b being connected to lead 44, in which the normally open switch 7 (controlled by the drivers seat) is connected. The overload normally closed switch 19a is provided in branch 42b, whereas the accelerator switch 21 is provided in branch 42a. In the neutral position of the controller 7a, main contacts KA of a contactor KA and switches C1 and C2 are open. If an overload is on or engaged by the carrier for the purpose of raising the latter and the load, switch 19a opens and breaks the circuits for the travel motor 7 and pump motor 17. To efiect truck travel, with the seat switch 7' closed, lever 9 is initially operated to insure travel forward or reawardly and next the accelerator pedal 7b is operated to first position, contact on controller engages finger 1, switches C1 and C2 (which are cam operated to closed position similarly to switch 7csee Fig. 1) close thereby energizing contactor KA to close the contacts KA to complete a circuit through resistors and motor 7. Contacts KA and KD are mechanically interlocked, so that when KA closes KD opens; truck travels in the direction selected by operation of lever 9. If accelerator pedal 7b is returned to off position, switch C2 opens, thereby breaking the control circuit. However, if truck travel in first speed position continues and pedal 7b is moved to second speed position, switch C1 opens, but circuit is maintained through now closed normally open contacts KA of contactor KA and fingers R4 and R are connected together shorting out a section of the resistance; in the third speed position, finger R3 is connected to fingers R4 and R5, thereby shorting out another section of the resistance; in the fourth speed position finger R2 is connected to fingers R4, R5 and R3, thereby shorting out all external resistance; in the fifth speed position, finger R1 is connected to fingers R2, R3, R4 and R5, thereby inserting a resistance in parallel with the motor field, effecting truck travel at maximum speed. To effect dynamic braking, lever 9 is moved to its opposite position, thereby reversing the current through motor armature and finger 1 disengages contact on controller, contactor KA is deenergized opening its contacts KA and KA, and switch KD (which is spring loaded to close) closes. Truck speed cannot again be accelerated until controller is returned to first speed position. As the circuit is completed through the switch 21 in the second, third, fourth and fifth speed positions, switch 19a is ineffective in the event of load bumping.

To those skilled in the art to which my invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. My disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

What I claim is:

1. In a vehicle having a frame assembly, means for supporting one end of said frame assembly comprising a wheel, means for connecting said wheel to said frame assembly including a longitudinal member extending longitudinally of said frame assembly, means connecting one end of said longitudinal member to said frame assembly and comprising a cross member carried by said longitudinal member at said one end thereof and extending transversely thereof and on opposite sides thereof, abutment means fixed to said frame assembly on opposite sides of said longitudinal member, said cross member being positioned below said abutment means, means connecting said abutment means and said cross member for limited relative movement from a position in engagement with each other, spring means operatively connected between said abutment means and said cross member for urging said abutment means and said cross member apart and yieldable to permit engagement thereof, said spring means urging said abutment means and cross member to produce relative movement therebetween and separation thereof upon upward tilting movement of said one end of said frame assembly due to a load applied to said frame assembly at the opposite end thereof, a switch device, a switch actuating device for said switch device, means operatively connecting one of said devices to said frame assembly for movement therewith, and means operatively connecting the other of said devices to said longitudinal member for movement therewith, said switch actuating device operating said switch device upon a predetermined relative movement between said abutment members due to said upward movement of said frame assembly.

2. In a vehicle having a frame assembly, means comprising a wheel for supporting one end of said frame assembly, an axle assembly including a longitudinal member operatively connected to said wheel and extending longitudinally of the frame assembly, and means operatively connecting said longitudinal member to said frame assembly comprising a casing having a resilient seat member therein, said seat member having an opening therein for receiving one of the end portions of said longitudinal member, an abutment means on said frame assembly, said casing having a part movable therewith for cooperating with said abutment means in supporting said frame assembly, spring means operatively connected between said frame assembly and said casing for urging said casing and said part away from said abutment means, means for limiting the movement of said abutment means and said part in a direction away from each other, a switch device, a switch actuating device, means operatively connecting one of said devices to said longitudinal member for relative movement therewith with respect to said frame assembly and means operatively connecting the other of said devices to said frame assembly, said switch actuating device being operable to actuate said switch device upon a predetermined relative movement between said devices.

3. In a vehicle having a frame assembly, means comprising a wheel for supporting one end of said frame assembly, an axle assembly including a longitudinal member operatively connected to said wheel and extending longitudinally of the frame assembly, and means operatively connecting said longitudinal member to said frame :assembly comprising a casing. having a resilient .seat

longitudinal member, an abutment member on said frame assembly, a transverse member carried by said longitudinal member adjacent to said casing and positioned below said abutment member, meansinterconnecting said'abutment member and said transversemember for limited relative movement and comprising spring means for urging said transverse member from said abutment'member, a switch device, a switch actuating device, means operatively connecting one of said devices to said longitudinal member for relative movement therewithwith respect to said frame assembly and means connecting the other of said devices to said frame assembly for movement therewith, said switch actuating 1 device being operable to actuate said'switch device upon a predetermined rela tive movement between said'devices.

"4. In a vehicle having a frame assembly, means comprising a wheel for supporting one end of said frame 7 assembly, an axle assembly including a longitudinm member operatively connected to said wheel and extending longitudinally of the frame assembly, and means operatively connecting said longitudinal member to said frame assembly comprising a casing having a resilient seat member therein, said seat member having an opening therein for receiving one of the end portions of said longitudinal member, spaced horizontally aligned members on said frame assembly on opposite sides of said I longitudinal member, a generally horizontal transverse member carried by said longitudinal member and extending transversely of said longitudinal member on opposite'sides thereof belowsaid aligned members carried by said frame assembly, means interconnecting said aligned members and said transverse member for limited relative movement, spring'means operatively connected between said aligned members and said transverse mem her for urging the transverse member and the aligned members in a direction away from each other and yieldable to permit engagement thereof, a switch device, a switch actuating device, means operatively connecting one or" said devices to said longitudinal member for relative movement therewith with respect to said frame assembly and means operatively connecting the other of said devices to said frame assembly, said switch actuating device being operable'to actuate said switch idevice uponapredetermined relative movementbetween said devices.

5.,inQa'vehicle'having a frameiassemblyga pair of wheels for supporting one'end of said frameassembly; an axle assemblyincluding a longitudinal member inter: mediate and operatively connected to'said wheels and extending longitudinally of the frame assembly; and

means operatively connecting said longitudinal member to said frame assembly comprising a first and second casing each having a resilient seat member therein and respectively disposed adjacent to opposite end portions of said longitudinal member, said seat members each having an opening therein for receiving the adjacentend portion of said longitudinal rnembeij'means connecting said first casing to said'frame assembly, and means opera tively connecting the other of said casings to said frame assembly comprising abutment means-0n said frame assembly on opposite sides of said longitudinal member, a

generally horizontal transverse member carried by said 7 longitudinal member and extending transversely of said,

longitudinal member on opposite sides thereof below said abutment means'carried by said frame assembly, means interconnecting said transverse member and said abutment means for limited relative movement, spring means operatively connected between said abutment References Cited in the file of this patent UNITED STATES PATENTS' 2,653,841 Davies et al. Sept. 29, 1953 2,704,132 Marco Mar. 15, 1955 FOREIGN PATENTS Italy a Nov. 1:9, 1929