US2957588A - Collapsible serving trolleys - Google Patents

Description

Ot. 25, 1960 MULLER 2,957,588

COLLAPSIBLE SERVING TRQLLEYS Filed April 22, 1959 2 Sheets-Shoot 1 F I 10 21 II Fig.1

20 20 315 3416 & 14 14 Jnvemor: 4/ KARL MULLER WM 3% I ATTORNEYS Oct. 25, 1960 K. MULLER COLLAPSIBLE ssavmc TROLLEYS 2 Sheets-Sheet 2 Filed April 22, 1.959

Jnvenfor: KARL M'u'LLER o/hm 9 HTTORIVE-s United States Patent Bremshey and Karl Heinz Eickhorn, trading as the firm Bremshey 8: Co., Solingen-Ohligs, Germany Filed Apr. 22, 1959, Ser. No. 808,219

2 Claims. (Cl. 211-149) The invention relates to a serving trolley which can be folded flat when not in use. It is based on a known construction having a longitudinally divided table topwhich is supported on a frame consisting of longitudinal supporting bars and a double parallelogram at each end. Each of these end parallelograms is composed of three parallel vertical frame members and of link members which connect the vertical frame members at the ends and which are disposed horizontally when the trolley is set up. The two parts of the table top are supported on the upper pairs of links. Another table top of similar construction may be provided, which is fixed on the lower pairs of links.

The known trolleys of this type of construction are inconvenient to handle. To collapse the frame, the table tops have to be lifted, which requires a considerable amount of force in the case of large tables. At the same time, a foot must usually be placed on the frame to prevent it from being lifted from the ground instead of collapsing. In the known constructions, it is not necessary to lift any parts to unfold the frame, but on the other hand a number of successive manipulations are necessary to bring first one half of the table top and then the other into the position for use.

The aim of the invention is to make the trolley considerably easier and simpler to handle. It is based on the idea of using gravity both when folding together and when unfolding the frame, so that part of both these operations can take place entirely automatically. To initiate these operations it is only necessary to release a lock. After this, only quite simple and easy manipulations are necessary for those stages of the operation which do not take place automatically, as will be seen from the following description.

According to the invention, the outer vertical frame members of each parallelogram extend downwardly below the level of the bottom of the central vertical frame member by an amount which is less than the length of a link member and manually releasable locking means is provided which secure the frame in the open and in the collapsed position.

Securing the frame in the open position by a lock which can be released by hand involves the risk that the trolley may collapse while in use if the lock is accidentally released. To prevent this, two independent locking members are provided. These are actuated by separate releasing members, and each locking member secures the frame in the open position. In order to collapse the trolley, it is then necessary to actuate the two releasing members simultaneously, which is not likely to happen accidentally. Accidental actuation of one of the releasing members does not cause the frame to collapse.

The two independent locking members may also serve to secure the trolley in the collapsed position. This prevents the collapsed frame accidentally opening out during transport.

The idea of using two independent locking members I with separate releasing members may also be applied to serving trolleys in which the parallelogram linkage is not constructed in the above described manner.

A preferred constructional embodiment of a trolley in accordance with the invention is illustrated, by way of example in the accompanying drawings, in which Figure l is a perspective view of the trolley.

Figures 2 to 4 are simplified diagrams showing the trolley in three different positions.

, Figure 5 is an end view of the bottom end of a central vertical frame member showing part of the locking means on a larger scale, with the frame in the opening position.

Figure 6 is a section on the line VI-VI in Figure 5.

Figure 7 is a view similar to Figure 5 but with the frame collapsed.

Figure 8 is a longitudinal section through the upper end of a central vertical frame member showing the releasing member.

Referring to the drawings, the frame of the trolley shown in Figure 1 consists of longitudinal bars 10 and a parallelogram linkage at each end, connected to the ends of the longitudinal bars 10. Each parallelogram contains three parallel, vertical frame members 11 and 12, of which the outer members 1'2 are prolonged downwardly beyond the lower end 13 of the central member 11 and carry rollers 14 which rest on the ground. The parallelograms are each closed at the top and bottom by four links 15 and 16. The pairs of links are con nected in the middle to each other and to the central frame members 11 by pivots 17 and 18, and by pivots 19 and 20 to the outer frame members 12.

The halves 21 of a table top which is divided centrally along the line 22 rest on the upper links 15. Usually, a second similarly constructed table top 23 having a central dividing line 24 is fixed to the lower pair of links. When the frame is open the distance of the bottom end 13 of the central frame member 11 from the floor is less than the length of a link 16.

In the open position shown in Figure l, the parts are held in position by releasable locking members which, in the form of construction shown in the drawings, fix the links 16 to the central frame member 11. Locking members of this kind are provided at both ends of the frame and operate independently of each other.

In order to fold up the frame, both locking members have to be released simultaneously. If only one locking member is released accidentally, the trolley remains in its position of use. The releasing members are in the form of press buttons at the upper ends of the parts 25 of the central frame members 11, which are bent outwards beyond the end surface. These parts 25 form handles. The locks and releasing members will be hereinafter described in detail.

When both releasing members are actuated, the frame moves automatically, under the action of gravity, from the position shown in Figure l to the position shown in Figure 2, without exerting any force.

In order to fold up the frame completely, i.e. to bring it into the position shown in Figure 3, it is merely necessary to press the lateral edges of the upper table top 21 together in the direction of the arrows. When the position shown in Figure 3 is reached, the locks again fall into position and secure the parts in the folded position.

The collapsed frame does not rest on the rollers 14 but on the bottom end of the central strut 11, which now forms a foot, so that it can quite safely he leaned against a wall.

When the trolley is to be put into use again, the curved upper ends 25 of the central strut 11 are grasped and the locking members are released. This causes the pairs of links 15 and 16 to open out sideways under the action of gravity until the rollers 14 touch the ground. Again, no force is necessary for this. The position shown in Figure 2 is thus again reached. It is then only necessary to lift the handles slightly, as shown in Figure 4 until the pairs of links 15, 16 are horizontal and the locking members fall into the locking positions.

A'suitable form of construction for the locks is shown in Figures 5 to 8. As before mentioned, these locks are arranged at both ends of the trolley and do not cooperate with one another.

The central frame members '11 consist of tubes with a closure piece 26 at the bottom end. A helical spring 27 rests on this closure piece, and a piston 28 can be moved against the spring by a rod 29 which is movable longitudinally inside the tube 11. A bolt 30 is fixed to the piston 28. This bolt projects outwardly through a longitudinal slip 31 in the wall of the tube and has a locking nose 32.

The links 16 which are rotatable about a pin 18 in the tube 11 have sectors 34 in their inner ends, on the circumference of which sectors recesses 35 are formed. The locking nose 32 engages in these recesses when the frame is open as shown in Figure 5. When the locking nose 32 is released by the rod 29 against the force of the spring 27, the links 16 are unlocked. When the links have rotated through 90 in the described manner, the locking nose 32 again falls into the locking position and engages between the radial edges 36 of the sectors 34, thereby securing the links in the collapsed position.

The rod 29, as shown in Figlre 8, has a curved projection 37 extending right to the end of the curved handle 25 where it ends in a pin 38 which forms a press button, and is guided in a sleeve 39. Its free end lies in a widened bore 40 of the sleeve 39, so as to protect against accidental release. The button can easily be actuated by thumb pressure.

I claim:

1. A collapsible serving trolley comprising a pair of end frames each consisting of three parallel vertical members and pairs of link members pivotally connecting the outer vertical members to the central member so as to form two parallelograms, longitudinal members connecting said end frame, a longitudinally divided table top carried by said link members, said outer vertical members extending below the lower ends of said central vertical members by an amount less than the length of said link members whenever said trolley is in its opened position, said link members being capable of assuming an angular position with reference to said vertical members, in which position said lower ends of said central members are coplanar with the lower ends of said outer vertical members, and a pair of spring-loaded lock means each of which is capable of locking the members of said frames in the open position as well as in the collapsed position of said trolley, said lock means being manually releasable independently of, and simultaneously with, each other.

2. A collapsible serving trolley comprising a pair of end frames each consisting of three parallel vertical members and pairs of link members pivotally connecting the outer vertical members to the central member so as to form two parallelograms, longitudinal members connecting said end frames, a longitudinally divided table top carried by said link members, said outer vertical members extending below the lower ends of said central vertical members by an amount less than the length of said link members whenever said trolley is in its opened position, said vertical members having upward extensions adapted to serve as handles, said link members being capable of assuming an angular position with reference to said vertical members, in which position the lower ends of said central members are coplanar with the lower ends of said outer vertical members, lock means including a pair of spring-loaded locking pawls each pawl being capable of locking the members of said frames in the open position as well as in the collapsed position of said trolley, said lock means further including a pair of manually operable members operable independently of, and simultaneously with, each other, each of said manually operable members being disposed on one of said extensions of said vertical members and connected to one of said locking pawls and adapted when operated to release said locking pawls.

References Cited in the file of this patent UNITED STATES PATENTS 1,167,550 Forsyth Jan. 11, 1916 FOREIGN PATENTS 1,133,044 France Nov. 12, 1956

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