EP0124141B1

EP0124141B1 - Electrically operated lifting jack

Info

Publication number: EP0124141B1
Application number: EP19840200200
Authority: EP
Inventors: Giacomo Manassero
Original assignee: EMGI ENGINEERING Srl; Emgi Engineering Srl
Current assignee: Siv SpA Te Volvera Italie
Priority date: 1983-02-24
Filing date: 1984-02-15
Publication date: 1988-04-20
Also published as: ES8502404A1; DE3470514D1; AU2477384A; EP0124141A1; DK91684D0; MX155891A; DK91684A; ES529996A0; BR8400843A

Description

This invention relates to a lifting jack, and more specifically to its special construction and operation employing electric drive, but with the facility for alternative manual operation should the elec- . tricity supply fail.
In the automotive field, a manual operation of the jack for replacing a tire is particularly slow, laborious and disagreeable, especially when atmospheric conditions are bad as this operation has to be carried out in the open, and moreover in this emergency situation the automobile user has to assume a physically abnormal operating position which is particularly tiring after his immobility during driving, all this being further accentuated in the case of female drivers.
GB-A-7038 discloses a lifting jack comprising a member for coupling to a vehicle to be lifted, said coupling member being lifted by a threaded bar which is operationally connected by way of a reduction unit to an electric motor; the reduction unit comprises a first and a second shaft, the first shaft being connected to the motor and the second being drivingly connected at one end to the threaded bar and being adapted at the other end to receive a crank for manually operating the jack; said first shaft incorporates an eccentric section, rotation of which is arranged to cause a displacement of said first shaft away from the second shaft in order to release the engagement between the at least one gear of each shaft and to define two alternative mutual positions of the shafts, one being a position of withdrawal in which the respective gear is disengaged for the purpose of manual operation of the jack.
As disclosed, however, this lifting jack has been proposed for raising locomotives and other heavy objects, therefore, the reduction unit is not disposed in an arrangement of minimum bulk since this is not necessary when using the lifting jack for raising very big and heavy objects. The lifting jack of GB-A-7038, in fact, cannot be placed in a luggage car having too big size.
DE-A-3109985 discloses a lifting jack of the type comprising a member for coupling to the vehicle to be lifted from a base on which the jack also rests, said coupling member being lifted by rotating a threaded bar, wherein the threaded bar is rotated by a low voltage electric motor operationally connected to the bar by way of a reduction unit constituted by two gears in cascade fixed on to parallel shafts, of which one is connected to the motor and the other to the bar.
This lifting jack does not provide the purpose of manual operation and the reduction unit and the motor are assembled in a housing of too big size as the motor is parallel to the threaded bar.
The main object of the invention is to propose a lifting jack in which the various components are disposed one above the other in an arrangement of minimum bulk when not operating to the advantage of accessibility of the respective vehicle compartment.
These object and advantage together with others, which will be apparent from the detailed description given hereinafter, are attained by a lifting jack comprising a member for coupling to a vehicle to be lifted, said coupling member being lifted by a threaded bar which is operationally connected by way of a reduction unit to an electric motor; said reduction unit comprising a first and a second shaft, the first shaft being connected to the motor and the second being drivingly connected at one end to the threaded bar and being adapted at the other end to receive a crank for manually operating the jack; said first shaft incorporating an eccentric section rotation of which is arranged to cause a displacement of said first shaft away from the second shaft in order to release the engagement between the at least one gear of each shaft and to define two alternative mutual positions of the shafts, one being a position of approach in which the respective gear is engaged for the purpose of electrical operation of the jack, the other being a position of withdrawal in which the respective gear is disengaged for the purpose of manual operation of the jack characterised in that a first and a second set of gears are mounted in cascade on the first and the second shafts respectively, the shafts are arranged parallel to each other, the axis of the motor is arranged parallel to the shafts and the motor is a low voltage electric motor for which the electrical supply is provided by the vehicle battery by way of a cable adapted to be inserted into the vehicle cigarette lighter socket.
The invention is described hereinafter in the form of two different embodiments of the jack to which the electrical operating device according to the invention is applied, with reference to the accompanying drawings in which:

Figures 1 and 2 are side elevations of two types of jack both comprising the electrical operating device according to the invention;
Figure 3 is an upper exploded view corresponding to the jack of Figure 1, but showing in detail the components of the electrical operating device according to the invention;
Figure 4 is a side view of the jack of Figure 2, in its operating state;
Figure 5 is a partial view to an enlarged scale of the lower end of the jack of Figures 2 and 4 in its retracted state;
Figure 6 is a constructional assembly detail of the components of the upper part of the jack of Figures 2, 4 and 5, in partial section on the line VI-VI of Figure 2.

In Figures 1 and 3, the reference numeral 1 indicates the threaded bar housed in known manner in the box casing 2 which is welded lowerly at 3 to the base 4 for support on the ground, and is provided laterally with a hollow support 5 in which at 6 there is hinged the shank 7 which is swivelled when in operation into the angular engagement position 7a for lifting the load but has its end housed in the plastic socket 8 (Figure 1) when not operating.
According to the new specific characteristic, to the top of the casing 2 there is connected by known means a metal container 9 which is of approximately parallepipedal geometry, is covered with a coating of plastic material (not shown) for aesthetic and accident-prevention purposes, and contains a low voltage electric motor 10, for which in the case of automobile application the supply can be the automobile battery, provided by inserting the respective cable into the known cigarette lighter socket.
From said motor 10 there emerges through hole 101 the pinion 12, which has helical teeth and thus operates with reduced noise and vibration (Figure 3).
With it there engages the gear 15 of the motion reduction unit, which is formed by two sets of gears of normal cylindrical toothing 15,16,17,18 and 19, 20, 21, plus a fourth gear, not shown, which engages in the gear 15 while the gears 16 and 19, 17 and 20, and 18 and 21 engage with each other.
The gears 15, 16,17,18 are carried by the shaft 13, while the gears 19, 20, 21 (plus that not shown because hidden by the gear 19) are fixed on to the shaft 14. The shafts 13 and 14 are parallel.
All said gears are contained in cascade in the housing 22, which is constructed of cast light alloy and is suitably closed by the cover 24, by means of the screws 23 which are screwed into the bored bosses 9a of the container 9 (Figure 3), thus also retaining the housing itself.
On the inner end of the shaft 14 comprising the spline 14a there is fixed by means of a known key the output bevel gear 25, which is directly coupled with the corresponding orthogonal gear 26, fixed to the upper end of the threaded bar 1.
As shown in the figures, the shaft 14 emerges from the lower support boss 27 of the cover 24, and the shaft 13 emerges through hole 100 from the upper boss 28.
According to a further characteristic of the invention, this latter shaft is provided with an offset central diametrical sector 29 arranged to perform a specific function described hereinafter, and its end 30 is provided with a facet 31 and a bore 32, for housing and locking the inner end 32a of the lever 33 by means of the bolt 34 and spacer 34a. _°
Said lever 33, constructed of special harmonic steel, is configured with a slightly offset profile comprising a joining step 35, in order to allow it to operate with a high level of elasticity, whereas the opposite end 36, i.e. the end outwards from the aforesaid end, is fixed by a screw 37 and spacer 38 to the boss 39 which forms one of the corresponding set of bosses which are positioned angularly spaced-apart and comprise stiffening ribs 23a, their purpose being to fix the cover 24 to the corresponding housing 22.
The jack operates as follows.
On pressing the rocker switch 11, the electric motor 10 is started and by way of its pinion 12 rotates the set of reduction gears contained in the housing 22, and of which the terminal bevel gear 26 drives the threaded bar 1 at low uniform speed, to cause raising and subsequent lowering of the support and load lifting shank 7, by two separate and opposite positionings of said switch 11.
Advantageously, said switch 11 is of open centre configuration, which operates only while manual pressure is applied, i.e. on removal of pressure the electrical supply, i.e. its operation, is interrupted, so that when the operator withdraws, the travel movement of the jack immediately stops, with the obvious advantage of general accident prevention.
The effective operability of the device with reference to its new components, its validity, and its comfortable and safe handling are perfectly apparent.
A further useful aspect is that if for any reason the electrical supply to the motor 10 should fail, the jack is able to be set for conventional manual operation.
In such an emergency, the outer end 36 of the lever 33 is removed from the boss 39 of the cover 24 and is fixed to the other boss 40, in which case because of the eccentricity of the sector 29 of the shaft 13, its gears 15,16,18 are no longer in direct engagement with the corresponding gears of the shaft 14, i.e. this latter becomes radially displaced from the shaft 13.
In such circumstances, the emergency angle crank 42 comprising a knurled operating knob 43 is fitted on to the flattened end 41 of the shaft 14, to thus enable the operator to proceed with the conventional method, even if only momentarily, thus allowing the necessary tyre changing operation to be completed.
The aforegoing relates to the application of the electrical device according to the invention to a conventional jack, but in which however certain difficulties often arise, and in particular the excessive and non-uniform intensity of the mechanical stresses, leading to variously directed forces which negatively affect the floor of the vehicle, thus causing instability during lifting. A description will now be given of a further application of the device according to the invention to a lifting device which comprises a lever system, of which the operational linkage is able to align the respective end loading points of those parts which make contact in operation, along a trajectory coextensive with the respective curve followed as the vehicle is tilted, with reference to Figures 2, 4, 5 and 6.
The jack according to the invention is essentially composed of a metal flanged support 51, comprising two spaced-apart lateral lugs 52 welded to it at 52a, and between which is positioned the mobile support 53, provided with end projections 54 of continuous profile.
The central sector 55 of the support 53 houses one end of the threaded bar 56 by way of the thrust bearing 57, which bar, after passing through the housing 22 containing the reduction gear 15-21 described heretofore with reference to Figure 3, emerges by way of its flattened end 30 for connecting the crank 42 comprising the knurled knob 43, for the purpose of any necessary emergency manual operation of the jack.
In contrast, in the embodiment of Figures 1 and 3, the shaft 14 comprises at its exit from the reduction unit 22 a bevel gear 25. Within the said two lateral lugs 52 of the flange 51, and more specifically to the projections 54 of the mobile support 53 which emerge by way of their ends 58 in a torsionally rigid manner, there is welded the box section of U cross-section 59, which is provided with an angular base 60 for resting on the ground 61. In addition, in order to facilitate its mounting on said mobile support 53, the box section 59 is provided in the upper part of its two side flanges 62 with an end slot 63, which opens into the circular housing hole 64.
Again for the purposes of said assembly, the respective opposing two projections 54 of the mobile support 53 have reduced-diameter profiles with a semi-circular cross-section 65 which extends beyond the axis 66 passing through the centre of the circle, in order to allow non-removable disengagement of the box section 59 during its operation described hereinafter.
The lever 69 is hinged, In a manner which allows it to swivel, to the inside of the flanges 62 of the box section 59, for example by means of the bolt 67 with locking nut 68, and is configured as two parallel spaced-apart flat sections between which there is positioned, by means of the bolt and nut 70, the ball joint 71 which comprises an internal thread engaging with the end 72 of said bar 56.
The lever 69 is joined upperly by a weld 73 to the bracket 74, which is provided on one side with a circular recess 75, and further provided with a pin 76 welded at 77 and retaining by way of the bore 79 the plate 78 which makes lifting contact with the vehicle floor after being centered in the slot of the floor by means of the shank 80.
To extend the application of the jack to various types of automobile, the plate 78 for reasons of stability during lifting can also comprise a central appendix for housing in the cavity 75, and be provided with a circular section piece arranged to rest on the outside of the pin 76.
Again for universal application, the lever 69 instead of being as shown can be hinged in a lower position by means of the further hole or other holes 81 provided in the respective flanges 62 of the box section 59.
The jack device of Figures 2, 4,5 and 6 operates as follows. When a tire has to be changed or other operations performed, the operator starts the electric motor 10 by means of the known switch, to cause rotation of the threaded bar 56.
In this emergency situation, this latter rises to consequently swivel the lever 69 and press against the vehicle floor by way of the plate 78, so that with the box section 59 vertically positioned on the ground 61 by way of its base 60, the respective end loading points A and B of the contacting lifting plate 78 and of the foot 60 resting on the ground (Figure 4) become aligned along the trajectory C.
Said trajectory C remains coextensive with the curve D followed by the vehicle during its lifting, thus leading to an advantageous gradual and uniform distribution of mechanical stresses, the consequent short length of operational travel of the bar 56 obviating any stumbling movement along the floor or counter-productive interference therewith.
As a further advantage, the components according to the invention, which are covered by an aesthetic accident-prevention coating, become disposed one above the other in an arrangement of minimum bulk when not operating, as shown in Figure 5, to the advantage of accessibility of the respective vehicle compartment. Only two types of lifting jack have been described and illustrated, however the electrical device according to the invention can be applied with the same advantages to any other type of currently commercially available jack.

Claims

1. A lifting jack comprising a member (7, 74) for coupling to a vehicle to be lifted, said coupling member being lifted by a threaded bar (1, 56) which is operationally connected by way of a reduction unit (15-18; 19-21) to an electric motor (10); said reduction unit comprising a first (13) and a second (14) shaft, the first shaft (13) being connected to the motor and the second (14) being drivingly connected at one end to the threaded bar and being adapted at the other end to receive a crank (42) for manually operating the jack; said first shaft (13) incorporating an eccentric section (29), rotation of which is arranged to cause a displacement of said first shaft (13) away from the second shaft (14) in order to release the engagement between the at least one gear (15-18; 19-21) of each shaft and to define two alternative mutual positions of the shafts, one being a position of approach in which the respective gear is engaged for the purpose of electrical operation of the jack, the other being a position of withdrawal in which the respective gear is disengaged for the purpose of manual operation of the jack characterised in that a first (15-18) and a second (19-21) set of gears are mounted in cascade on the first (13) and the second (14) shafts respectively, the shafts are arranged parallel to each other, the axis of the motor (10) is arranged parallel to the shafts and in the motor is a low voltage electric motor for which the electrical supply is provided by the vehicle battery by way of a cable adapted to be inserted into the vehicle cigarette lighter socket.

2. A jack as claimed in claim 1 in which the threaded bar (56) is screwed at one end in a hinged manner to one end of a lever (69), the other end of which lever is hinged to a section bar (59) which itself is hinged at its upper end to the reduction unit (22) and rests on the ground at its lower end (60); the lever (69) comprising members (74-78) for anchoring to the vehicle to be lifted following the rotation and consequent swivel movement of said bar (59).

3. A jack as claimed in claim 2 characterized in that the threaded bar (56) is connected to the reduction unit (22) by way of a thrust bearing (57) mounted in a mobile support (53), in which said section bar (59) is hinged.

4. A jack as claimed in claim 2 characterized in that when the vehicle is lifted laterally, the respective end loading points of the curved base (D) of the section bar (59) which rests on the ground (B) and of the lifting members (A) are aligned along a changing trajectory (C) coextensive with the curve which the vehicle to be lifted follows during its lifting such that the lower loading points moves along the curved base section (D) when the vehicle is being raised or lowered.