CA2510843A1

CA2510843A1 - Seat framework for bus

Info

Publication number: CA2510843A1
Application number: CA002510843A
Authority: CA
Inventors: Luc Belair; Pierre Cossette; Richard Jobidon; Alain Amplemann
Original assignee: Multina Inc
Current assignee: Individual
Priority date: 2005-06-22
Filing date: 2005-06-22
Publication date: 2006-12-22
Also published as: MXPA06003745A; US20060290180A1

Abstract

A seat for use in motor vehicles, such as school buses, is described wherein the seat frame and the shape of seat belt anchors are modular components. Also described is the construction of the seat backrest frame which permits to make the components modular. The seat backrest cover is interchangeable.

Description

Seats that can be dismantled 1. Application The present invention is related to seats which are used in motor vehicles, and more specifically to the type of seats found in school buses.
The present invention mainly touches the modularity and interchangeability concepts. To do so, the following elements will be specified in the patent:
~ The modularity of the seat's frame.
~ The modularity and the shape of the seat belt anchors.
~ The construction of the seat backrest frame which permits us to make modular components.
~ The assembling of the seat backrest cover which allows seat cover interchangeablity.
~ The assembling of the lower seat's cover which allows cover interchangeability.

2. Actual models The actual seat models already exist and have so for several years. They are of two (2) types:
~ Models in two parts.
~ Models in three parts.
The two parts model consists of the seat frame and the seat cushion. The seat frame is mainly built with welded metallic tubes. The frame is composed of a backrest, a seat, a pedestal and a wall support. To this frame is added an upholstered backrest composed of foam and of a vinyl cover. The vinyl cover is fixed to the seat frame with metallic staples. The seat cushion is composed of a piece of wood, foam and a vinyl cover. The foam is placed on the piece of wood and is covered with a piece of vinyl. The cover is stapled to the wood piece.
Two spring clips and two pivoting clips are used under the cushion. They serve to solidly attach the seat cushion to the seat frame.
The three part model is identical to the two part model, except for the seat frame. The seat frame is composed of only one (1) backrest, one (1) seat and one (1) wall bracket.
The pedestal is an independent part that is installed onto the frame before the bus seat is installed.
Furthermore, because each bus configuration is different from one customer to another, each frame is available according to a variety of sizes (45 inches, 39 inches, 34 inches, 30 inches, 26 inches and 18 inches) and heights (high backrest and low backrest).
These ways of doing have four main disadvantages:
~ The quantity and size of the parts do not permit an efficient optimization of the supply sources.
~ The low proportion of standard parts (only the pedestal in the three part model) in order to maximise the use of certain parts no matter what width or height is required.
~ The shape of the seat frame does not permit efficient shipping of the seats from the supplier to the client.

~ The structure's shape does not permit easy seat installation in the bus for the client.
With the actual ways of proceeding, optimization of supplying sources is difficult. The most expensive part in the seat frame is of a very big size and shape which does not permit a large quantity of parts per container. In the context of internationalization of supplying sources, the cost of transportation for this part increases the client's purchasing price.
Furthermore, when transporting the finished parts from the supplier to the client, it is difficult to wrap the parts efficiently in order to optimize space and avoid damaging them.
This fact results in increasing the costs associated to transportation of the finished parts to the client.
Before installing the seats, employees must carry the seat inside the bus.
Because space is very limited inside a bus, it is difficult for the employees to manoeuvre the seats without damaging them. In certain cases, the weight of the seat is so important that it provokes backaches.
Finally, when fastening the seat in the bus, holes must be drilled using the seats as template.
Seeing that the seat occupies the majority of space available in the bus, it is difficult for the employee to install himself adequately to drill the holes. Most of the time, the holes that are needed to be drilled are located under the seat and not easily accessible.
Furthermore, once in the bus, if the manufacturer wants to change the color of the cover, they must remove the seat completely from the vehicle and replace with new seats.
This way of doing becomes very costly because they must unbolt the wall brackets and pedestals to remove all the seats. Moreover, as the seats are difficult to manipulate, there is a high risk of damaging the cover.
The seat belt anchors actually used are made up of a plate in which two holes have been cut:
~ The first hole is round and serves to fasten the seat belt plate to the seat frame.
~ The second hole is oblong. The belt is inserted inside and sewn onto itself.
This way, the belt is independent of the seat belt anchor.
This way of doing has two main disadvantages:
~ A hole must be drilled in the frame in order to attach the plate. This procedure weakens the frame. Usually, for reinforcement, the manufacturer strengthens the steel structure by thickening the tube's walls and the plates used. This increases the seat's weight.
~ As the part is fastened with a bolt onto the seat's frame, all the traction load is exerted onto the bolt. This means that the dimension of the bolt required must be increased in order to resist the load which adds to the total weight of the seat.
For the manufacturer, the seat belts must be directly attached to the structure of the seat assembly. This is a difficult operation because it obliges the employee to manipulate the entire frame.
Assembling of the back and bottom covers is fixed. The back cover is stapled to a part that is usually made up of a piece of wood which is screwed to the backrest frame. The bottom is stapled to a piece of plywood which serves as a support to the seat foam. The foam used is foam which is assembled when cut and glued, according to the shape required. This foam generally has a simple shape and a low density. Because staples are used, it is impossible for the manufacturers to change the color of the seat covers.
The seat back frame is a critical issue in the design of a seat. Federal safety standards require that the seat of all school buses was made using a backrest that gives by a certain amount when impacted by a force exceeding a predetermined magnitude. They required also that the backrest was rigid enough to not collapse in case of a crash. Also, to prevent injuries to the passenger, the backrest should be able to absorb a certain amount of energy without collapsing. See, for example, Federal Motor Vehicle Safety Standards (FMVSS) 222 (49 CFR 571.222), which are incorporated for reference herein.
To succeed in passing the FMVSS test, actual manufacturers use, on their seat frames, different combinations of tubing (round or square) welded together, straightened or bended to outline the shape of the seat. To calibrate the strength required on the backrest structure, some manufacturers modify the tubing's wall thickness or add a metal rod inside the tubing to increase the strength to meet FMVSS requirements.

3. Invention ~umm~ry 3.I The school bus seat modularity The reason for the modularity is to permit:
~ Easier transportation of the sub-assemblies manufactured for the supplier;
~ Maximization of standard parts;
~ More efficient transportation of the seat from the supplier to the client;
~ Installatior_ of seats in the buses made easier.
To do so, the seat has been dismantled into several parts according to the following criteria:
~ Minimise the complexity of parts that vary according to height and width of the seats.
~ Maximise the complexity of standard parts.
~ Minimise the time required and the quantity of bolts needed to assemble different parts.
This way of doing permitted us to divide the seat structure according to the following parts:
~ Pedestal assembly (1) ;
~ Lower seat assembly (2) ;
~ Backrest assembly (3) ;
~ Central beam assembly (4) ;
~ Assembled wall brackets (5) ;
~ Seat belt clamps (6) ;
~ The support bolts (7) ;
~ The seat cushion with the cover (8) ;
~ The upholstered seat cushion on a piece of wood (9).

Then invention's configuration allows us to standardize the pedestal assembly (1), the central beams (4) and the wall bracket assemblies (5) which are the most complicated parts. This allows optimization of the cost price for these parts by increasing the quantity per container and therefore lowering transportation costs. The complexity of the lower seat assembly (2) and the backrest frame (3) is less and allows made to measure fabrication according to height and width required for the seat.
The seat cushion (8) is directly installed onto the lower seat assembly frame (2) with screw. The backrest cushion is directly upholstered onto the backrest frame (3). A
plastic clip system is used to hold the cover into place.
Usually, installation at the client's facilities is done in the following manner:
~ The wall bracket assembly (5) is fastened to the side wall. A nut and bolt system is used to fasten the wall bracket using pre-drilled holes in the wall.
~ The central beam (4) is inserted into the wall bracket assembly (5). A clip on the beam is ,. , "... , u~cu w mum m iii matt.

The pedestal assembly (1) is inserted at the beam's other extremity (4). A
clip on the beam is used to hold it in place and to insure a good spacing between the wall bracket and the pedestal.
At this time, it is possible to drill holes in the floor by using the pedestal assembly (1) as a template. Nuts and bolts are used to fasten the pedestal (1) to the floor.
Because, there is no cushion on the seat, it is easier for the employee to drill holes using the seat pedestal as template.

~ The backrest frame (3) assembled with the backrest cushion is inserted into the vertical tube that is located near the pedestal (1) and wall bracket (5). A stopper is provided inside the pedestal (1) and wall bracket (S) tubes in order to place the backrest (3) in the required position.

The lower seat frame assembly (2) along with its cushion (8) is inserted into the horizontal openings made in the pedestal (1) and wall bracket (5). The seat frame's round part (8) is inserted through the pedestal (1), and the central beam and is fastened to the tube's wall on the backrest frame (3).
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Pedestal hole 1 .

~ A support bolt (7) is screwed behind the seat (on the pedestal's side) and inserts itself into the round part of the seat frame (8). When it is tightened, the end of the rod presses against the inside of the tube and blocks it there. The conic part of the rod secures the central beam (4) against the inside of the pedestal's (1) square tube.
r ~ A second bolt (7) is screwed into the back side of the seat (on the wall side) and inserts itself inside the round part of the seat's frame (2). When tightening, the end of the rod presses against the inside or the backrest tube and blocks it there. The conic part of the rod secures the central beam (4) against the inside of the wall bracket's (5) square tube.

When tightening, the front seat pin (2) inserts itself into the groove in the pedestal's frame (1).
Once tightened, the pin's position prevents the front of the seat from moving upwards which reduces rattling.

~ This way of doing permits us to fasten all parts together and therefore avoid rattling.
3.2 Backrest Frame Because of the modularity, we had to change the actual shape of the backrest frame. The new backrest frame was especially conceived to enable us to adjust the backrest's rigidity according to requirements demanded in standard FMVSS 222. To do so, the backrest tube is made up of two tubes of different diameters and thicknesses. Both tubes are of different dimensions in order to allow the tubes to be assembled one inside the other. The tube on the inside (1) composes the entire shape of the backrest. The tube on the outside (2) is sufficiently longer and more rigid to satisfy requirements of FMVSS 222. The upper end of the tube on the outside is welded to the tube on the inside to avoid it from moving.
Therefore, upon impact, both tubes will be subjected to a force which will bend them plastically towards the front. As only one end of the tubes is fastened, both tubes can, at the beginning of the impact, slide one against the other. After a certain time following the impact, the bending of the tubes will be such that they will no longer be able to slide one against the other. At that moment, an increase in energy will be required to bend the tubes further.
This variation in energy required to bend the backrest will allow us to control the passenger's deceleration when hitting the backrest during impact. By adjusting the dimension and the thickness of the tubes, it is therefore possible to meet with the standards required by FMVSS
222.

The seat belt anchors The reason for the invention is to permit positioning of the belt anchors at different areas on the seat in order to satisfy all the market requirements. Furthermore, they were conceived in such a way to distribute the load on a bigger surface and allow the belt anchors to be attached to the round tube without drilling the seat structure. To do so, the anchor has the shape of a collar (1).
The collar has a slightly larger opening than the dimension of the tube. This is done to permit the collar to bend over the beam when the bolt (3) is tightened. Thus, once it is tightened, it can no longer slide on the tube. The belt (2) of the seat belt is slipped through both oblong holes pierced in the collar's extremities. The belt is then sewn l4) together.

L
t 3.4 The backrest cover To allow the backrest cover to be replaced once the seat has been assembled, the cover must not be fastened with staples as it is usually done. To do so, we have elaborated a cover (2) that slips perfectly onto the backrest foam (4). At the extremity of the cover, two strips (5) of thin plastic are sewn on the cover. These strips, once the cover is in place, are inserted into a closed "C"
shape (3) which holds the strips in place. Once installed, the strips are visible. If the cover needs to be removed, we simply pull on these strips and the cover is removed without being damaged.
L

Claims

4. What needs to be protected, What is claimed and desired to be secured by Letters Patent is:

1. A modular seat for a vehicle seat composed of modular seat members that are assembled using 2 bolts.

2. The modular seat of claim 1, wherein the same seat members can be used to assemble a right hand seat and a left hand seat.

3. The modular seat of claim 1, wherein the seat members are composed of a backrest cushion assembly, a bottom cushion assembly, a pedestal, a wall support, a beam and seat belt anchors if required.

4. The modular seat of claim 1, wherein the seat members are separately assembled or are pre-assembled by welding or other method prior the assembly.

5. The seat members of claim 3, wherein the bottom cushion assembly is composed of a seat cover, a molded foam, a plywood base and a frame.

6. The seat members of claim 3, wherein the beam is a round tube that is squared at both ends.

7. The modular seat of claim 1, wherein the bolt of the pedestal side is used to screw the end of the bottom seat cushion's metal frame through the pedestal, the beam and the backrest cushion assembly metal frame.

8. The modular seat of claim 1, wherein the bolt of the wall support side is used to screw the end of the bottom seat cushion's metal frame through the wall bracket, the beam and the backrest cushion assembly's metal frame.

9. The bottom cushion assembly of claim 5, wherein the frame is composed of a shaped channel and 2 rods at both ends of the shaped channel.

10. The frame of claim 9, wherein the rod has a bigger diameter on the shaped channel side and a smaller diameter at the end side. The transition between the two diameters is composed of a chamfer.

11. The rod of claim 10, wherein the chamfer, when the rod is pulled once is screwed, is squeezed into the hole in the beam to hold the beam in place and prevent rattling.

12. The rod of claim 10, wherein the smaller diameter end is pulled once it is screwed, is squeezes the inside portion of the backrest frame to prevent rattle.

13. The seat members of claim 3, wherein the seat belt anchoring apparatus for attachment to a seat including:
a. an anchor clamp sliding onto a tubing;
b. a bolt being tied down to the anchor around the tubing;
c. a nut for screwing the bolt in;
d. a seat belt webbing.

14. The anchoring apparatus of claim 13 wherein the anchor's clamp material is made of metal.

15. The anchoring apparatus of claim 13 wherein the anchors clamp material is made of plastic.

16. The anchoring apparatus of claim 13 wherein the anchor clamp is tied down using more than one bolt.

17. The anchoring apparatus of claim 13 wherein the screw is screwed in using a nut welded to the anchor clamp.

18. The anchoring apparatus of claim 13 wherein the screw is screwed into a hole tapped in the anchors clamp.

19. The anchoring apparatus of claim 13 wherein the seat belt webbing forming a loop through the bracket and being sewn on itself.

20. The anchoring apparatus of claim 13 wherein the inner side of the anchors clamp is shaped in a manner to grip onto the tubing and preventing the anchor clamp from sliding once it is tied.

21. The anchor clamp of claim 20 wherein the inner shape can be in the shape of teeth.

22. The modular seat of claim 3, wherein the back rest cushion assembly including a metal backrest frame, a cushion made of a soft plastic material that is inserted over the metal backrest frame, a trim cover made of vinyl fabric that is upholstered over the cushion, a plastic strip that is sewn on the trim cover and that is inserted ino the closed "C-shaped"
metal part to hold the trim cover in place.

23. The backrest cushion assembly of claim 22, wherein the metal backrest frame, said frame including two tubular elements inserted one inside the other, a metal angle that is between the lower section of the tubular elements and that is welded on both sides of the tubular elements, a closed "C-shaped" metal part that is welded onto the angle, a metal sheet welded to the top on the tubular elements and the bottom section that is welded to the angle.

24. The backrest frame according to claim 23, wherein said tubular elements are made of round tubing of different diameter so they can be insert one inside the other.
They are welded together at the top section of the smallest one and they are free to slide one against the other at the other end (bottom section of the backrest).

25. The backrest frame according to claim 23, wherein said closed "C-shaped"
made from plastic or metal that is used to hold the seat cover in place by holding the plastic strip sewn onto the backrest trim cover.