AUXILIARY WHEEL HOLDER

Abstract: An auxiliary wheel holder for pallet trucks, of the type provided with lifting forks and small fork wheels (10) foldably mounted thereon, is detachably mountable on said lifting forks. To this end, the auxiliary wheel holder has a frame in the form of several juxtaposed support arms (6) detachably connected to the outer parts (8) of said lifting forks and carrying two or more auxiliary wheels (2) which have a radius of rotation greater than that of the fork wheels (10), and are independently and freely rotatable on a common axle (4) mounted on said support arms (6).

Description: AUXILIARY WHEEL HOLDER All pallet trucks manufactured in Europe are com- ' pletely adapted to European pallet standard. This means, among other things, that the wheels mounted underneath the lifting forks of the truck have, for 5 considerations of space, a very small wheel diameter which may amount maximally to 85 mm, because of the ground clearance of the pallet which is about 100 mm. In actual practice, this limited size of the radius of rotation of the fork wheels means that the mobility 10 of the pallet truck in the horizontal plane is reduced considerably and frequently directly obstructed already by insignificant irregularities in the base on which the truck is moved. Such irregularities may be in the form of small stones on a gravel surface, thresholds, 15 or the surface of a floor grating. A further obstacle to heavily loaded small diameter wheels is a substrate which is too soft, for example sand. Also mattings of different types must be regarded as such a soft substrate. 20 The present invention aims at greatly reducing the rolling resistance of the small fork wheels by replacing these wheels in a simple manner by far larger and broader wheels mounted as a unit in a detachable auxiliary wheel holder. 25 One embodiment of such an auxiliary wheel holder is shown in the accompanying drawings in which Fig. 1 illu¬ strates from above and from the side the auxiliary wheel holder before it is connected to a but partly shown \ pallet truck, and Fig. 2 is a lateral view of the 30 pallet truck with the auxiliary wheel holder connected thereto. The auxiliary wheel holder according to the invention and illustrated in the drawings comprises three large transport or auxiliary wheels 2 which are independently 35 and freely rotatable on a common axle 4 which in turn is mounted or secured in a frame 6. The frame comprises four support arms 6 designed such that they can be manually inserted into the open outer parts of the truck lifting forks. In order to fix the mutual positions and spacings of all juxtaposed support arms 6, there is provided, in addition to the axle 4, a cross bar 12 extending through all of the support arms. A smaller cross bar 14 is used for pairwise fixing of said support arms. The smaller cross bar 14 may be provided with a recess 20 for accommodating fork wheels 10 foldably mounted on the lifting forks and adapted, in folded-up position, to be inserted in order to lock the auxiliary wheel holder. Alternatively, the auxiliary wheel holder may be locked by means of a locking hook 22 provided on the attachment of the fork wheels 10. The hook 22 fits into a recess 24 in the support arms 6 of the auxiliary wheel holder. The auxiliary wheel holder is mounted in the following manner. The pallet truck is pushed underneath a pallet with the fork wheels 10 in folded-up position. Then the pallet truck is pumped with the pallet and the load to maximum heigth, whereby steering wheels 16 and the fork wheels 10 are subjected to load. The support arms 6 of the auxiliary wheel holder are inserted into the outer parts 8 of the lifting forks, and the forks are lowered so that the weight of the load on the fork wheels 10 is transferred to the auxiliary wheels 2. The fork wheels 10 are folded up to lock the support arm 6, whereupon the goods can be transported by means of the auxiliary wheels 2. To remove the auxiliary wheel holder, the procedure is the reverse. To facilitate insertion of the auxiliary wheel holder, two of the support arms 6 are slightly extended at 26. Fig. 2 illustrates the auxiliary wheel holder inserted in the outer parts 8 of the forks of the pallet truck, with folded-up fork wheels 10 and ready for use. When the auxiliary wheel holder is not used, it is stored in the manner illustrated by the dash- ; . \ dot lines A in Fig. 2. 5 The above description imposes no restriction on the ba-sic idea of the invention. For example, the support arms 6 may be designed to completely or partly encompass the outer parts 8 of the lifting forks of the pallet truck, instead of being inserted therein. 10 The support arms 6 can cooperate with guide and locking means mounted on the outer or inner side of the outer parts 8 of the lifting forks. Furthermore, the auxiliary wheels 2 may have a dimension which, to a varying degree, is greater or smaller than the dimension of 15 the steering wheels 16 of the pallet truck. One of the advantages of the auxiliary wheel holder according to the invention is that it can be moved between and used with different standard type pallet trucks, which brings not only economic advan- 20 tages in terms of a small number of auxiliary wheel holders for many pallet trucks and few or no modifi¬ cations of the trucks themselves, but also considerable freedom of use and less maintenance. Because of its construction, the auxiliary wheel 25 holder according to the invention also imposes no restrictions, naturally within reasonable limits, upon the diameter, width and other construction de¬ tails of the auxiliary wheels 2. A further advantage is that the auxiliary wheel 30 holder enables the fork wheels 10 and the auxiliary wheels 2 to "collaborate" when passing over obstacles ' ■ "^S such as tresholds etc. by alternating the load on the respective set of wheels, such that one set of wheels can be moved past or over the obstacle before 35 or after the other set.

Claims: CLAIMS 1. Auxiliary wheel holder for pallet trucks of the type having lifting forks and fork wheels (10) f'oldably mounted thereon, c h a r a c t e r i s e d in that at least two auxiliary wheels (2) having a larger radius of rotation than the fork wheels (10) are mutually and freely rotatable in a frame (6) which is detachably connectible to the outer parts (8) of said lifting forks. 2. Auxiliary wheel holders as claimed in claim 1/ c h a r a c t e r i s e d in that the auxiliary wheels (2) are mounted on a common axle (4) mounted in the frame (6) . 3. Auxiliary wheel holder as claimed in claim l or 2, c h a r a c t e r i s e d in that the frame (6) is lockable on the outer parts (8) under the action of the fork wheels (10) in folded-up position, by a locking hook (22) or in some other manner. 4. Auxiliary wheel holder as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the frame is formed of several juxtaposed support arms (6), the mutual spacing of which is determined by a cross bar (12) extending through said support arms.

Inventors: RYTTERSSON OVE, RYTTERSSON, OVE
Applicants: RYTTERSSON OVE, RYTTERSSON, OVE
Application year: 1987
Main classification: B66F9
IPC codes: B62B3